View source for Naked mole-rat

{{Short description|Burrowing eusocial rodent}}
{{pp-semi-indef|small=yes}}
{{Speciesbox
| name = Naked mole-rat
| fossil_range = {{fossil range|4.3|0}}<small>Early [[Pliocene]] - Recent</small><ref name="Jarvis 2002">{{cite journal |last1=Jarvis |first1=Jennifer U. M. |last2=Sherman |first2=Paul W. |title=Heterocephalus glaber |journal=Mammalian Species |date=December 2002 |volume=2002 |issue=706 |page=1-9 |doi=10.1644/1545-1410(2002)706<0001:HG>2.0.CO;2}}</ref>
| image = Nacktmull.jpg
| status = LC
| status_system = IUCN3.1
| status_ref =<ref name="iucn">Maree, S. & Faulkes, C. (2016). ''Heterocephalus glaber''. The IUCN Red List of Threatened Species 2016 (errata version published in 2017). {{doi|10.2305/IUCN.UK.2016-3.RLTS.T9987A22184136.en}}</ref>
| display_parents = 3
| grandparent_authority = Landry, 1957<ref name="Landry" /><ref name="Patterson" />
| parent_authority = [[Eduard Rüppell|Rüppell]], 1842<ref name="Ruppell1842" />
| taxon = Heterocephalus glaber
| authority = [[Eduard Rüppell|Rüppell]], 1842<ref name="Ruppell1842" />
| range_map = Heterocephalus glaber dis.png
| range_map_caption = Distribution of the naked mole-rat
}}
[[File:Heterocephalus glaber June 2019.webm|thumb|Various aged naked mole-rats]]

The '''naked mole-rat''' ('''''Heterocephalus glaber'''''), also known as the '''sand puppy''',<ref name="Kingdon1984">{{Cite book |last=Kingdon |first=Jonathan |url=https://books.google.com/books?id=tSCodorMbrUC&pg=PA489 |title=East African Mammals: An Atlas of Evolution in Africa, Volume 2, Part B: Hares and Rodents |date=1 July 1984 |publisher=University of Chicago Press |isbn=978-0-226-43720-0 |page=489 |name-list-style=vanc}}</ref> is a burrowing rodent native to the [[Horn of Africa]] and parts of [[Kenya]], notably in [[Greater Somalia|Somali]] regions.{{r|Jarvis 2002|}} It is closely related to the [[blesmol]]s and is the only species in the [[genus]] '''''Heterocephalus'''''.<ref name="Buffenstein Park Hanes Artwohl 2012 pp. 1055–1074" /> 

The naked mole-rat exhibits a highly unusual set of physiological and behavioral traits that allow it to thrive in a harsh underground environment; most notably its being the only mammalian [[Thermoregulation|thermoconformer]] with an almost entirely [[ectothermic]] (cold-blooded) form of body temperature regulation,<ref>{{Cite web |last=Welsh |first=Jennifer |name-list-style=vanc |date=2011-10-12 |title=Naked Mole Rat Genome May Hold Key to Long Life |url=http://www.livescience.com/16516-naked-mole-rat-genome-longevity.html |access-date=2013-03-23 |publisher=LiveScience |department=Human Health & Longevity}}</ref> as well as exhibiting [[eusociality]], a complex social structure including a reproductive division of labor, separation of reproductive and non-reproductive castes, and cooperative care of young.<ref>{{cite journal |last1=Sherman |first1=Paul W. |last2=Lacey |first2=Eileen A. |last3=Reeve |first3=Hudson K. |last4=Keller |first4=Laurent |title=The eusociality continuum |journal=Behavioral Ecology |date=Spring 1995 |volume=6 |issue=1 |page=102-108 |doi=10.1093/beheco/6.1.102}}</ref> The closely related [[Damaraland mole-rat]] (''Fukomys damarensis'') is the only other known eusocial mammal.<ref name="O'Riain and Faulkes, (2008)">{{Cite book |last1=O'Riain |first1=M. Justin |title=Ecology of Social Evolution |last2=Faulkes |first2=Chris G. |chapter=African Mole-Rats: Eusociality, Relatedness and Ecological Constraints |date=2008 |publisher=Springer |isbn=978-3-540-75956-0 |editor-last=Korb |editor-first=Judith |pages=207–223 |doi=10.1007/978-3-540-75957-7_10 |editor-last2=Heinze |editor-first2=Jörgen |name-list-style=vanc}}</ref><ref>{{Cite journal |vauthors=Burland TM, Bennett NC, Jarvis JU, Faulkes CG |date=May 2002 |title=Eusociality in African mole-rats: new insights from patterns of genetic relatedness in the Damaraland mole-rat (''Cryptomys damarensis'') |journal=Proceedings. Biological Sciences |volume=269 |issue=1495 |pages=1025–30 |doi=10.1098/rspb.2002.1978 |pmc=1690998 |pmid=12028759}}</ref> Naked mole-rats lack pain sensitivity in their skin, and have very low [[metabolism|metabolic]] and [[Respiration (physiology)|respiratory rates]]. The animal also is remarkable for its longevity and resistance to [[cancer]] and [[oxygen deprivation]].

While formerly considered to belong to the same family as other African mole-rats, [[Bathyergidae]], more recent investigation places it in a separate family, '''Heterocephalidae'''.<ref name="Patterson">{{Cite journal |last1=Patterson |first1=Bruce D. |last2=Upham |first2=Nathan S. |name-list-style=vanc |date=November 2014 |title=A newly recognized family from the Horn of Africa, the Heterocephalidae (Rodentia: Ctenohystrica) |journal=Zoological Journal of the Linnean Society |volume=172 |issue=4 |pages=942–963 |doi=10.1111/zoj.12201 |doi-access=free}}</ref><ref>{{Cite book |last=Kingdon |first=Jonathan |url=https://books.google.com/books?id=p1hMCAAAQBAJ |title=The Kingdon Field Guide to African Mammals: Second Edition |publisher=Princeton University Press |year=2015 |isbn=978-1472925312 |location=Princeton, N.J. |pages=224 |name-list-style=vanc}}</ref><ref>{{Cite book |last1=Wilson |first1=Don E. |title=Handbook of the Mammals of the World Volume 6: Lagomorphs and Rodents |last2=Lacher |first2=Thomas E. |last3=Mittermeier |first3=Russell A. |publisher=Lynx Edicions |year=2016 |isbn=978-8494189234 |location=Barcelona |page=312 |name-list-style=vanc}}</ref>

==Description==
Typical individuals are {{convert|8|to|10|cm|in|0|abbr=on}} long and weigh {{convert|30|to|35|g|oz}}. Breeding females are larger and may weigh well over {{convert|50|g|oz}}, the largest reaching {{convert|80|g|oz}}. They are well adapted to their underground existence. Their eyes are quite small, and their visual acuity is poor. Their legs are thin and short; however, they are highly adept at moving underground and can move backward as fast as they can move forward. Their large, protruding teeth are used to dig and their lips are sealed just behind the teeth, preventing soil from filling their mouths while digging.{{r|Jarvis 2002|}}<ref>{{Cite web |title=Naked Mole-Rat |url=http://nationalzoo.si.edu/Animals/SmallMammals/fact-nakedmolerat.cfm |url-status=dead |archive-url=https://web.archive.org/web/20150426144754/http://nationalzoo.si.edu/Animals/SmallMammals/fact-nakedmolerat.cfm |archive-date=2015-04-26 |website=Meet Our Animals |publisher=[[Smithsonian National Zoo Park]]}}</ref> About a quarter of their musculature is used in the closing of their jaws while they dig. They have little hair (hence the common name) and wrinkled pink or yellowish skin. They lack an insulating layer in the skin.

==Physiology==
===Metabolism and respiration===
The naked mole-rat is well adapted to the limited availability of [[oxygen]] within the tunnels of its typical habitat. It has underdeveloped [[lung]]s and its [[hemoglobin]] has a high affinity for oxygen, increasing the efficiency of oxygen uptake.<ref>{{Cite journal |last1=Maina |first1=J.N. |last2=Maloiy |first2=G.M.O. |last3=Makanya |first3=A.N. |date=September 1992 |title=Morphology and morphometry of the lungs of two East African mole rats, Tachyoryctes splendens and Heterocephalus glaber (Mammalia, Rodentia) |journal=[[Zoomorphology]] |volume=112 |issue=3 |pages=167–179 |doi=10.1007/BF01633107 |s2cid=23738702}}</ref><ref name="Science">{{Cite journal |vauthors=Park TJ, Reznick J, Peterson BL, Blass G, Omerbašić D, Bennett NC, Kuich PH, Zasada C, Browe BM, Hamann W, Applegate DT, Radke MH, Kosten T, Lutermann H, Gavaghan V, Eigenbrod O, Bégay V, Amoroso VG, Govind V, Minshall RD, Smith ES, Larson J, Gotthardt M, Kempa S, Lewin GR |date=April 2017 |title=Fructose-driven glycolysis supports anoxia resistance in the naked mole-rat |journal=Science |volume=356 |issue=6335 |pages=307–311 |bibcode=2017Sci...356..307P |doi=10.1126/science.aab3896 |pmid=28428423 |doi-access=free|hdl=2263/60326 |hdl-access=free }}</ref><ref name="WP">{{Cite news|title=Naked mole-rats are now even weirder: Without oxygen, they live like plants|language=en-US|newspaper=Washington Post|url=https://www.washingtonpost.com/news/speaking-of-science/wp/2017/04/20/naked-mole-rats-are-now-even-weirder-without-oxygen-they-live-like-plants/|access-date=2023-02-07|issn=0190-8286
|last=Guarino|first= Ben |date=23 April 2017
}}</ref> It has a very low respiration and metabolic rate for an animal of its size, about 70% that of a mouse, thus using oxygen minimally.<ref>{{Cite journal |last=Buffenstein |first=Rochelle |date=1 November 2015 |title=The Naked Mole-Rat: A New Long-Living Model for Human Aging Research |journal=[[The Journals of Gerontology|The Journals of Gerontology: Series A]] |volume=60 |issue=11 |pages=1369–1377 |doi=10.1093/gerona/60.11.1369 |pmid=16339321 |doi-access=free}}</ref> In response to long periods of hunger, its metabolic rate can be reduced by up to 25 percent.<ref name="Science" />

The naked mole-rat survives for at least 5 hours in air that contains only 5% oxygen; it does not show any significant signs of distress and continues normal activity. It can live in an atmosphere of 80% {{chem|CO|2}} and 20% oxygen. In zero-oxygen atmosphere, it can survive 18 minutes apparently without suffering any harm (but none survived a test of 30 minutes). During the anoxic period it loses consciousness, its heart rate drops from about 200 to 50 beats per minute, and breathing stops apart from sporadic breathing attempts. When deprived of oxygen, the animal uses [[fructose]] in its [[Anaerobic respiration|anaerobic]] [[glycolysis]], producing [[lactic acid]]. This pathway is not inhibited by [[acidosis]] as happens with glycolysis of glucose.<ref name="Science" /><ref name="WP" /> As of 2017, it was not known how the naked mole-rat survives acidosis without tissue damage.<ref>{{Cite journal |vauthors=Storz JF, McClelland GB |date=April 2017 |title=Rewiring metabolism under oxygen deprivation |journal=Science |volume=356 |issue=6335 |pages=248–249 |bibcode=2017Sci...356..248S |doi=10.1126/science.aan1505 |pmc=6661067 |pmid=28428384}}</ref>

===Thermoregulation===
The naked mole-rat does not regulate its body temperature in typical mammalian fashion. They are [[thermoconformer]]s rather than [[thermoregulator]]s in that, unlike other mammals, body temperature tracks ambient temperatures. The relationship between oxygen consumption and ambient temperature switches from a typical [[poikilotherm]]ic pattern to a [[homeotherm]]ic mode when temperature is at 29&nbsp;°C or higher.<ref name="Daly et al., (1997)">{{Cite journal |vauthors=Daly TJ, Williams LA, Buffenstein R |date=April 1997 |title=Catecholaminergic innervation of interscapular brown adipose tissue in the naked mole-rat (''Heterocephalus glaber'') |journal=Journal of Anatomy |volume=190 ( Pt 3) |issue=3 |pages=321–6 |doi=10.1046/j.1469-7580.1997.19030321.x |pmc=1467613 |pmid=9147219}}</ref> At lower temperatures, naked mole-rats can use behavioral thermoregulation. For example, cold naked mole-rats huddle together or seek shallow parts of the burrows that are warmed by the sun. Conversely, when they get too hot, naked mole-rats retreat to the deeper, cooler parts of the burrows.

===Pain insensitivity===
The skin of naked mole-rats lacks [[neurotransmitter]]s in their [[Cutaneous nerve|cutaneous sensory fibers]]. As a result, the naked mole-rats feel no pain when they are exposed to acid or [[capsaicin]]. When they are injected with [[substance P]], a type of neurotransmitter, the pain signaling works as it does in other mammals but only with capsaicin and not with acids. This is proposed to be an adaptation to the animal living in high levels of [[carbon dioxide]] due to poorly ventilated living spaces which would cause acid to build up in their body tissues.<ref>{{Cite journal |vauthors=Park TJ, Lu Y, Jüttner R, Smith ES, Hu J, Brand A, Wetzel C, Milenkovic N, Erdmann B, Heppenstall PA, Laurito CE, Wilson SP, Lewin GR |date=January 2008 |title=Selective inflammatory pain insensitivity in the African naked mole-rat (''Heterocephalus glaber'') |journal=PLOS Biology |volume=6 |issue=1 |pages=e13 |doi=10.1371/journal.pbio.0060013 |pmc=2214810 |pmid=18232734 |doi-access=free }}</ref>

Naked mole-rats' substance P deficiency has also been tied to their lack of the histamine-induced itching and scratching behavior typical of rodents.<ref>{{Cite journal |vauthors=Smith ES, Blass GR, Lewin GR, Park TJ |date=May 2010 |title=Absence of histamine-induced itch in the African naked mole-rat and "rescue" by Substance P |journal=Molecular Pain |volume=6 |issue=1 |pages=1744–8069–6–29 |doi=10.1186/1744-8069-6-29 |pmc=2886013 |pmid=20497578 |doi-access=free }}</ref>

===Resistance to cancer===
Naked mole-rats have a high resistance to tumours, although it is likely that they are not entirely immune to related disorders.<ref name="delaney">{{Cite journal |vauthors=Delaney MA, Ward JM, Walsh TF, Chinnadurai SK, Kerns K, Kinsel MJ, Treuting PM |date=May 2016 |title=Initial Case Reports of Cancer in Naked Mole-rats (''Heterocephalus glaber'') |journal=Veterinary Pathology |volume=53 |issue=3 |pages=691–6 |doi=10.1177/0300985816630796 |pmid=26846576 |doi-access=free}}</ref> A potential mechanism that averts [[cancer]] is an "over-crowding" gene, [[p16 (gene)|p16]], which prevents cell division once individual cells come into contact (known as "[[contact inhibition]]"). The cells of most mammals, including naked mole-rats, undergo contact inhibition via the gene [[p27 (gene)|p27]] which prevents cellular reproduction at a much higher cell density than p16 does. The combination of p16 and p27 in naked mole-rat cells is a double barrier to uncontrolled cell proliferation, one of the [[hallmarks of cancer]].<ref name="SELUANOV">{{Cite journal |vauthors=Seluanov A, Hine C, Azpurua J, Feigenson M, Bozzella M, Mao Z, Catania KC, Gorbunova V |date=November 2009 |title=Hypersensitivity to contact inhibition provides a clue to cancer resistance of naked mole-rat |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=106 |issue=46 |pages=19352–7 |bibcode=2009PNAS..10619352S |doi=10.1073/pnas.0905252106 |pmc=2780760 |pmid=19858485 |doi-access=free}}</ref>

In 2013, scientists reported that the reason naked mole-rats do not get cancer can be attributed to an "extremely high-molecular-mass [[hyaluronan]]" (HMW-HA) (a natural sugary substance), which is over "five times larger" than that in cancer-prone humans and cancer-susceptible laboratory animals.<ref name="NYT-20130619">{{Cite news |last=Zimmer |first=Carl |name-list-style=vanc |date=19 June 2013 |title=A Homely Rodent May Hold Cancer-Fighting Clues |work=[[New York Times]] |url=https://www.nytimes.com/2013/06/19/science/a-homely-rodent-may-hold-cancer-fighting-clues.html |access-date=20 June 2013}}</ref><ref>{{Cite journal |last=Callaway |first=Ewen |date=19 June 2013 |title=Simple molecule prevents mole rats from getting cancer |journal=Nature |doi=10.1038/nature.2013.13236 |s2cid=88241415}}</ref><ref>{{Cite news |date=19 June 2013 |title=Naked mole-rat gives cancer clues |work=BBC News |url=https://www.bbc.co.uk/news/health-22961694 |access-date=21 June 2013 |vauthors=Briggs H}}</ref> The scientific report was published a month later as the cover story of the journal ''[[Nature (journal)|Nature]]''.<ref name="NATURE-20130619">{{Cite journal |vauthors=Tian X, Azpurua J, Hine C, Vaidya A, Myakishev-Rempel M, Ablaeva J, Mao Z, Nevo E, Gorbunova V, Seluanov A |date=July 2013 |title=High-molecular-mass hyaluronan mediates the cancer resistance of the naked mole rat |journal=Nature |volume=499 |issue=7458 |pages=346–9 |bibcode=2013Natur.499..346T |doi=10.1038/nature12234 |pmc=3720720 |pmid=23783513}}</ref> A few months later, the same University of Rochester research team announced that naked mole-rats have [[ribosome]]s that produce extremely error-free proteins.<ref name="Holmes">{{Cite journal |last=Holmes |first=Bob |date=4 May 2021 |title=Genetic tricks of the longest-lived animals |url=https://knowablemagazine.org/article/health-disease/2021/genetic-tricks-longest-lived-animals |journal=Knowable Magazine |doi=10.1146/knowable-050421-5 |access-date=25 March 2022 |s2cid=235543595|doi-access=free }}</ref><ref>{{Cite journal |vauthors=Azpurua J, Ke Z, Chen IX, Zhang Q, Ermolenko DN, Zhang ZD, Gorbunova V, Seluanov A |date=October 2013 |title=Naked mole-rat has increased translational fidelity compared with the mouse, as well as a unique 28S ribosomal RNA cleavage |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=110 |issue=43 |pages=17350–5 |bibcode=2013PNAS..11017350A |doi=10.1073/pnas.1313473110 |pmc=3808608 |pmid=24082110 |doi-access=free}}</ref> Because of both of these discoveries, the journal ''[[Science (journal)|Science]]'' named the naked mole-rat "Vertebrate of the Year" for 2013.<ref>{{Cite journal |date=December 2013 |title=Breakthrough of the year 2013. Notable developments |journal=Science |volume=342 |issue=6165 |pages=1435–41 |doi=10.1126/science.342.6165.1444 |pmid=24357296 |doi-access=free}}</ref>

In 2016, a report was published that recorded the first ever discovered malignancies in two naked mole-rats.<ref name="delaney" /><ref name="NYT-20160219">{{Cite news |last=St. Fleur |first=Nicholas |name-list-style=vanc |date=February 19, 2016 |title=Two Naked Mole Rats, Seemingly Immune to Cancer, Got Cancer |work=[[New York Times]] |url=https://www.nytimes.com/2016/02/20/science/two-naked-mole-rats-seemingly-immune-to-cancer-got-cancer.html |access-date=February 20, 2016}}</ref><ref name="TS-2016">{{Cite web |year=2016 |title=Cancer detected in naked mole rats |url=http://www.the-scientist.com/?articles.view/articleNo/45269/title/Cancer-Detected-in-Naked-Mole-Rats/ |access-date=February 15, 2016 |publisher=The Scientist |vauthors=Grens K}}</ref> However, both animals were captive-born at zoos, and hence lived in an environment with 21% atmospheric oxygen compared to their natural 2–9%, which may have promoted tumorigenesis.<ref>{{Cite journal |vauthors=Welsh JS, Traum TL |date=November 2016 |title=Regarding Mole Rats and Cancer |journal=Veterinary Pathology |volume=53 |issue=6 |pages=1264–1265 |doi=10.1177/0300985816646434 |pmid=27733703 |doi-access=free}}</ref>

The [[Golan Heights blind mole-rat]] (''Spalax golani'') and the [[Judean Mountains blind mole-rat]] (''Spalax judaei'') are also resistant to cancer, but by a different mechanism.<ref>{{Cite journal |last=Cormier |first=Zoe |date=5 November 2012 |title=Blind mole rats may hold key to cancer |journal=Nature |doi=10.1038/nature.2012.11741 |s2cid=101691159}}</ref>

In July 2023 a study reported the transference of the gene responsible for HMW-HA from a naked mole rat to mice leading to improved health and an approximate 4.4 percent increase in median lifespan for the mice.<ref>{{Cite journal |last1=Zhang |first1=Zhihui |last2=Tian |first2=Xiao |last3=Lu |first3=J. Yuyang |last4=Boit |first4=Kathryn |last5=Ablaeva |first5=Julia |last6=Zakusilo |first6=Frances Tolibzoda |last7=Emmrich |first7=Stephan |last8=Firsanov |first8=Denis |last9=Rydkina |first9=Elena |last10=Biashad |first10=Seyed Ali |last11=Lu |first11=Quan |last12=Tyshkovskiy |first12=Alexander |last13=Gladyshev |first13=Vadim N. |last14=Horvath |first14=Steve |last15=Seluanov |first15=Andrei |date=2023-08-23 |title=Increased hyaluronan by naked mole-rat Has2 improves healthspan in mice |journal=Nature |volume=621 |issue=7977 |pages=196–205 |language=en |doi=10.1038/s41586-023-06463-0 |pmid=37612507 |bibcode=2023Natur.621..196Z |s2cid=261100218 |issn=0028-0836|pmc=10666664 }}</ref><ref>{{Cite web |last=Valich |first=Lindsey |date=2023-08-23 |title=Longevity gene from naked mole rats extends lifespan of mice |url=https://www.rochester.edu/newscenter/gene-transfer-hmw-ha-naked-mole-rats-extends-mice-lifespan-565032/ |access-date=2023-08-28 |website=News Center |language=en-US}}</ref>

===Longevity===
Naked mole-rats can live longer than any other rodent, with lifespans in excess of 37&nbsp;years; the next longest-lived rodent is the [[Crested porcupine|African porcupine]] at 28&nbsp;years.<ref>{{cite journal |last1=Sherman |first1=Paul W. |last2=Jarvis |first2=Jennifer U.M. |title=Extraordinary life spans of naked mole-rats (Heterocephalus glaber) |journal=Journal of Zoology |date=November 2002 |volume=253 |issue=3 |page=307-311 |doi=10.1017/S0952836902001437}}</ref><ref name="Buffenstein Craft 2021 p. 246">{{cite book |last1=Buffenstein |first1=Rochelle |last2=Craft |first2=Wendy |title=The Extraordinary Biology of the Naked Mole-Rat |series=Advances in Experimental Medicine and Biology |chapter=The Idiosyncratic Physiological Traits of the Naked Mole-Rat; a Resilient Animal Model of Aging, Longevity, and Healthspan |publisher=Springer International Publishing |publication-place=Cham |year=2021 |volume=1319 |isbn=978-3-030-65942-4 |issn=0065-2598 |doi=10.1007/978-3-030-65943-1_8 |page=246|pmid=34424518 |s2cid=237269233 }}</ref><ref name="Ruby Smith Buffenstein 2018">{{cite journal |last1=Ruby |first1=J Graham |last2=Smith |first2=Megan |last3=Buffenstein |first3=Rochelle |title=Naked mole-rat mortality rates defy Gompertzian laws by not increasing with age |journal=eLife |publisher=eLife Sciences Publications, Ltd |volume=7 |date=January 24, 2018 |pages=e31157 |issn=2050-084X |doi=10.7554/elife.31157 |pmid=29364116 |pmc=5783610 |doi-access=free }}</ref> The mortality rate of the species does not increase with age, and thus does not conform to that of most mammals (as frequently defined by the [[Gompertz–Makeham law of mortality|Gompertz-Makeham law of mortality]]).<ref name="Ruby Smith Buffenstein 2018" /> Naked mole-rats are highly resistant to cancer,<ref name="Buffenstein R. 2008 439–45">{{Cite journal |vauthors=Buffenstein R |date=May 2008 |title=Negligible senescence in the longest living rodent, the naked mole-rat: insights from a successfully aging species |journal=Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology |volume=178 |issue=4 |pages=439–45 |doi=10.1007/s00360-007-0237-5 |pmid=18180931 |s2cid=13598294}}</ref> and maintain healthy [[Blood vessels|vascular]] function longer in their lifespan than shorter-living rats.<ref>{{Cite journal |vauthors=Csiszar A, Labinskyy N, Orosz Z, Xiangmin Z, Buffenstein R, Ungvari Z |date=August 2007 |title=Vascular aging in the longest-living rodent, the naked mole rat |journal=American Journal of Physiology. Heart and Circulatory Physiology |volume=293 |issue=2 |pages=H919–27 |doi=10.1152/ajpheart.01287.2006 |pmid=17468332 |s2cid=19584646}}</ref> Queens age more slowly than nonbreeders.<ref name="x300">{{cite journal |last=Horvath |first=Steve |last2=Haghani |first2=Amin |last3=Macoretta |first3=Nicholas |last4=Ablaeva |first4=Julia |last5=Zoller |first5=Joseph A. |last6=Li |first6=Caesar Z. |last7=Zhang |first7=Joshua |last8=Takasugi |first8=Masaki |last9=Zhao |first9=Yang |last10=Rydkina |first10=Elena |last11=Zhang |first11=Zhihui |last12=Emmrich |first12=Stephan |last13=Raj |first13=Ken |last14=Seluanov |first14=Andrei |last15=Faulkes |first15=Chris G. |last16=Gorbunova |first16=Vera |display-authors=5 |title=DNA methylation clocks tick in naked mole rats but queens age more slowly than nonbreeders |journal=Nature Aging |volume=2 |issue=1 |date=2021-12-23 |pmid=35368774 |pmc=8975251 |doi=10.1038/s43587-021-00152-1 |pages=46–59}}</ref>

The mechanisms underlying naked mole-rat longevity are debated, but are thought to be related to their ability to substantially reduce their [[metabolism]] in response to adverse conditions, and so prevent aging-induced damage from [[oxidative stress]]. This has been referred to as "living their life in pulses".<ref>{{Cite web |date=2007-10-16 |title=Ugly Duckling Mole Rats Might Hold Key To Longevity |url=https://www.sciencedaily.com/releases/2007/10/071015225336.htm |access-date=2009-03-11 |publisher=Sciencedaily.com}}</ref> Their longevity has also been attributed to "protein stability".<ref name="stability">{{Cite journal |vauthors=Pérez VI, Buffenstein R, Masamsetti V, Leonard S, Salmon AB, Mele J, Andziak B, Yang T, Edrey Y, Friguet B, Ward W, Richardson A, Chaudhuri A |date=March 2009 |title=Protein stability and resistance to oxidative stress are determinants of longevity in the longest-living rodent, the naked mole-rat |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=106 |issue=9 |pages=3059–64 |bibcode=2009PNAS..106.3059P |doi=10.1073/pnas.0809620106 |pmc=2651236 |pmid=19223593 |doi-access=free}}</ref> Because of their extraordinary longevity, an international effort was put into place to sequence the [[genome]] of the naked mole-rat.<ref>{{Cite web |title=Proposal to Sequence an Organism of Unique Interest for Research on Aging: Heterocephalus glaber, the Naked Mole-Rat |url=http://genomics.senescence.info/sequencing/heterocephalus.html |access-date=2009-04-30 |publisher=Genomics.senescence.info}}</ref> A draft genome was made available in 2011<ref>{{Cite web |title=Naked Mole-Rat Database |url=http://mr.genomics.org.cn |access-date=5 July 2011 |publisher=Naked Mole-Rat Database 2011}}</ref><ref>{{Cite web |title=Naked Mole-Rat Genome Resource |url=http://naked-mole-rat.org/ |access-date=5 July 2011 |publisher=Naked Mole-Rat Genome Resource 2011}}</ref><ref>{{Cite journal |vauthors=Kim EB, Fang X, Fushan AA, Huang Z, Lobanov AV, Han L, Marino SM, Sun X, Turanov AA, Yang P, Yim SH, Zhao X, Kasaikina MV, Stoletzki N, Peng C, Polak P, Xiong Z, Kiezun A, Zhu Y, Chen Y, Kryukov GV, Zhang Q, Peshkin L, Yang L, Bronson RT, Buffenstein R, Wang B, Han C, Li Q, Chen L, Zhao W, Sunyaev SR, Park TJ, Zhang G, Wang J, Gladyshev VN |date=October 2011 |title=Genome sequencing reveals insights into physiology and longevity of the naked mole rat |journal=Nature |volume=479 |issue=7372 |pages=223–7 |bibcode=2011Natur.479..223K |doi=10.1038/nature10533 |pmc=3319411 |pmid=21993625}}</ref> with an improved version released in 2014.<ref>{{Cite journal |vauthors=Keane M, Craig T, Alföldi J, Berlin AM, Johnson J, Seluanov A, Gorbunova V, Di Palma F, Lindblad-Toh K, Church GM, de Magalhães JP |date=December 2014 |title=The Naked Mole Rat Genome Resource: facilitating analyses of cancer and longevity-related adaptations |journal=Bioinformatics |volume=30 |issue=24 |pages=3558–60 |doi=10.1093/bioinformatics/btu579 |pmc=4253829 |pmid=25172923}}</ref> Its [[somatic number]] is [[Diploid|2n]] = 60.<ref name="Buffenstein Park Hanes Artwohl 2012 pp. 1055–1074">{{Cite book |last1=Buffenstein |first1=Rochelle |title=The Laboratory Rabbit, Guinea Pig, Hamster, and Other Rodents |last2=Park |first2=Thomas |last3=Hanes |first3=Martha |last4=Artwohl |first4=James E. |publisher=Elsevier |year=2012 |isbn=9780123809209 |pages=1055–1074 |chapter=Naked Mole Rat |doi=10.1016/b978-0-12-380920-9.00045-6 |chapter-url=https://www.sciencedirect.com/science/article/pii/B9780123809209000456 |s2cid=80673862}}</ref> Further [[transcriptome]] sequencing revealed that genes related to [[mitochondria]] and oxidation reduction are expressed more than they are in mice, which may contribute to their longevity.<ref>{{Cite journal |vauthors=Yu C, Li Y, Holmes A, Szafranski K, Faulkes CG, Coen CW, Buffenstein R, Platzer M, de Magalhães JP, Church GM |year=2011 |title=RNA sequencing reveals differential expression of mitochondrial and oxidation reduction genes in the long-lived naked mole-rat when compared to mice |journal=PLOS ONE |volume=6 |issue=11 |pages=e26729 |bibcode=2011PLoSO...626729Y |doi=10.1371/journal.pone.0026729 |pmc=3207814 |pmid=22073188 |doi-access=free}}</ref>

The [[DNA repair]] [[transcriptome]]s of the liver of humans, naked mole-rats, and mice were compared.<ref name="pmid26729707">{{Cite journal |vauthors=MacRae SL, Croken MM, Calder RB, Aliper A, Milholland B, White RR, Zhavoronkov A, Gladyshev VN, Seluanov A, Gorbunova V, Zhang ZD, Vijg J |date=December 2015 |title=DNA repair in species with extreme lifespan differences |journal=Aging |volume=7 |issue=12 |pages=1171–84 |doi=10.18632/aging.100866 |pmc=4712340 |pmid=26729707}}</ref> The maximum lifespans of humans, naked mole-rats, and mice are respectively c. 120, 30 and 3 years. The longer-lived species, humans and naked mole-rats, expressed DNA repair genes, including core genes in several DNA repair pathways, at a higher level than did mice. In addition, several DNA repair pathways in humans and naked mole-rats were up-regulated compared with mice. These findings suggest that increased DNA repair facilitates greater longevity, and also are consistent with the [[DNA damage theory of aging]].<ref>Bernstein H, Payne CM, Bernstein C, Garewal H, Dvorak K (2008). "[https://www.novapublishers.com/catalog/product_info.php?products_id=43247 Cancer and aging as consequences of un-repaired DNA damage] {{Webarchive|url=https://web.archive.org/web/20141025091740/https://www.novapublishers.com/catalog/product_info.php?products_id=43247 |date=2014-10-25 }}". In: ''New Research on DNA Damages'' (Editors: Honoka Kimura and Aoi Suzuki) [[Nova Science Publishers, Inc.]], New York, Chapter 1, pp. 1-47. open access, but read only {{ISBN|1604565810}} {{ISBN|978-1604565812}}</ref>

===Size===
Reproducing females become the dominant female, usually by founding new colonies, fighting for the dominant position, or taking over once the reproducing female dies. These reproducing females tend to have longer bodies than that of their non-reproducing counterparts of the same skull width. The measurements of females before they became reproductive and after show significant increases in body size. It is believed that this trait does not occur due to pre-existing morphological differences but to the actual attainment of the dominant female position.<ref>{{Cite journal |vauthors=Young AJ, Bennett NC |date=November 2010 |title=Morphological divergence of breeders and helpers in wild Damaraland mole-rat societies |journal=Evolution; International Journal of Organic Evolution |volume=64 |issue=11 |pages=3190–7 |doi=10.1111/j.1558-5646.2010.01066.x |pmid=20561049 |s2cid=28456413|doi-access=free }}</ref> As with the reproductive females, the reproductive males also appear to be larger than their non-reproducing counterparts but the difference is smaller than in females. These males also have visible outlines of the testes through the skin of their abdomens. Unlike the females, there are usually multiple reproducing males.<ref name="Jarvis, J. U. M. 1993">{{Cite journal |vauthors=Jarvis JU, Bennett NC |year=1993 |title=Eusociality has evolved independently in two genera of bathyergid mole-rats — but occurs in no other subterranean mammal |journal=Behavioral Ecology and Sociobiology |volume=33 |issue=4 |pages=253–260 |doi=10.1007/bf02027122 |s2cid=37118289}}</ref>

===Chronobiology===
The naked mole-rat's subterranean habitat imposes constraints on its [[circadian rhythm]].<ref name=":1">{{Cite book |last1=Park |first1=T.J. |title=Encyclopedia of Animal Behavior |last2=Lewin |first2=G.R. |last3=Buffenstein |first3=R. |year=2010 |isbn=978-0-08-045337-8 |pages=505–512 |chapter=Naked Mole Rats: Their Extraordinary Sensory World |doi=10.1016/b978-0-08-045337-8.00152-2}}</ref> Living in [[Photoperiodism|constant darkness]], most individuals possess a free-running [[Actigraphy|activity pattern]] and are active both day and night, sleeping for short periods several times in between.<ref name=":1" /> However, colonies do not exhibit synchronized circadian sleep-wake cycles.<ref>{{cite journal |last1=Davis-Walton |first1=Jennifer |last2=Sherman |first2=Paul W. |title=Sleep arrhythmia in the eusocial naked mole-rat |journal=Naturwissenschaften |date=1994 |volume=81 |issue=6 |page=272-275 |doi=10.1007/BF01131581}}</ref>

==Ecology and behavior==

===Distribution and habitat===
The naked mole-rat is native to the drier parts of the tropical grasslands of East Africa, predominantly southern [[Ethiopia]], [[Kenya]], and [[Somalia]].{{r|Jarvis 2002|}}<ref name="Sherman 1991">{{Cite book |last1=Sherman |first1=Paul W. |title=The Biology of the Naked Mole-rat |last2=Jarvis |first2=Jennifer U.M. |last3=Alexander |first3=Richard D. |publisher=Princeton University Press |year=1991 |isbn=978-0691024486 |location=Princeton, N.J. |name-list-style=vanc}}</ref>

===Roles===
[[File:Model of naked mole-rat soldiers, workers, and queen.jpg|thumb|upright=1.35|Model of naked mole-rat soldiers, workers, and queen, a social structure similar to the castes of the [[eusocial]] insects]]

The naked mole-rat was the first mammal found to be [[eusocial]]. The [[Damaraland mole-rat]] (''Fukomys damarensis'') is the only other eusocial mammal currently known.<ref>{{cite journal |last1=Jarvis |first1=Jennifer U. M. |last2=O'Riain |first2=M. Justin |last3=Bennett |first3=Nigel C. |last4=Sherman |first4=Paul W. |title=Mammalian eusociality: a family affair |journal=Trends in Ecology and Evolution |date=2 February 1994 |volume=9 |issue=2 |page=47-51 |doi=10.1016/0169-5347(94)90267-4}}</ref>

The social structure of naked mole-rats is similar to that of [[ant]]s, [[termite]]s, and some [[bee]]s and [[wasp]]s.{{r|Sherman 1991|}}<ref>{{Cite journal |last=Jarvis |first=Jennifer |date=May 1981 |title=Eusociality in a Mammal: Cooperative Breeding in Naked Mole-Rat Colonies |journal=Science |volume=212 |issue=4494 |pages=571–573 |bibcode=1981Sci...212..571J |doi=10.1126/science.7209555 |jstor=1686202 |pmid=7209555 |s2cid=880054}}</ref><ref name="Marshall 2014">{{Cite web |last=Marshall |first=Michael |name-list-style=vanc |date=17 October 2014 |title=Eight ugly animals we should save anyway |url=http://www.bbc.com/earth/story/20141017-eight-ugly-animals-we-should-save |access-date=3 January 2015 |website=BBC Earth}}</ref> Only one female (the queen) and one to three males reproduce, while the rest of the members of the colony function as workers.<ref>{{Cite journal |last1=Sherman |first1=Paul W. |last2=Jarvis |first2=Jennifer U. M. |last3=Braude |first3=Stanton H. |date=August 1992 |title=Naked Mole Rats |journal=Scientific American |volume=267 |issue=2 |pages=72–79 |bibcode=1992SciAm.267b..72S |doi=10.1038/scientificamerican0892-72 |jstor=24939178}}</ref> The queen and breeding males are able to breed at one year of age. Workers are sociologically but not physiologically sterile.<ref name="Marshall 2014" /> Smaller workers focus on gathering food and maintaining the nest, while larger workers are the tunnelers, and are the most reactive to threats.{{r|Sherman 1991|}} The non-reproducing females appear to be reproductively suppressed, meaning the ovaries do not fully mature, and do not have the same levels of certain hormones as the reproducing females.{{r|Sherman 1991|}} By contrast, there is little difference of hormone concentration between reproducing and non-reproducing males. In experiments where the reproductive female was removed or died, one of the non-reproducing females would take over and become sexually active. Non-reproducing members of the colony cooperate to care for the pups produced by the queen (usually their mother or sister). Workers keep the pups from straying out of the nest, groom the pups, and snuggle to keep them warm, extend tunnels in search of food, bring food to the nest, and defend pups from attacks by predators and foreign colonies.<ref name="Jarvis, J. U. M. 1993" />{{r|Sherman 1991|}}

====Queen and gestation====
The relationships between the queen and the breeding males may last for many years; other females are temporarily sterile. Queens live from 13 to 18&nbsp;years, and are extremely hostile to other females that attempt to exert physical dominance, or that produce hormones associated with becoming queens. When the queen dies, another female takes her place, often after a violent struggle with her competitors.{{r|Sherman 1991|}} Once established, the new queen's body expands the space between the [[vertebrae]] in her backbone to become longer and ready to bear pups.<ref>{{Cite web |title=San Diego's Animals. Mammals: Naked Mole-rat |url=http://www.sandiegozoo.org/animalbytes/t-naked_mole-rat.html |access-date=2013-03-23 |publisher=Sandiegozoo.org}}</ref> 

In the wild, naked mole-rats usually breed once a year, if the litter survives. In captivity, they breed all year long and can produce a litter every 80&nbsp;days.{{r|Sherman 1991|}}<ref name="ross">{{Cite book |last=Piper |first=Ross |url=https://archive.org/details/extraordinaryani0000pipe |title=Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals |publisher=Greenwood Press |year=2007 |isbn=978-0-313-33922-6 |location=Westport, Conn |author-link=Ross Piper |url-access=registration |name-list-style=vanc}}</ref> Gestation lasts about 70&nbsp;days. Litter size is typically 3 to 12 pups; the average litter size is 11-12 {{r|Sherman 1991|}}<ref name="Sherman 1999">{{cite journal |last1=Sherman |first1=Paul W. |last2=Braude |first2=Stanton |last3=Jarvis |first3=Jennifer U.M. |title=Litter sizes and mammary numbers of naked mole-rats: Breaking the one-half rule |journal=Journal of Mammalogy |date=August 1999 |volume=80 |issue=3 |page=720-733 |doi=10.2307/1383241}}</ref><ref>{{Cite web | archive-url = https://web.archive.org/web/20000118230736/http://www.news.cornell.edu/releases/Aug99/rat_mamm.hrs.html | archive-date = 18 January 2000|url = http://www.news.cornell.edu/releases/Aug99/rat_mamm.hrs.html | url-status=unfit | title = Counting mole-rat mammaries and hungry pups, biologists explain why naked rodents break the rules | date = 9 August 1999 | first = Roger | last = Segelken |website=news.cornell.edu}}</ref> The young are born blind and weigh about {{convert|2|g|oz|sigfig=1}}. The queen nurses them for the first month, after which the other members of the colony feed them [[feces|fecal pap]] until they are old enough to eat solid food.

In most female mammals the number of mammae is about double the average litter size.<ref>{{cite journal |last1=Gilbert |first1=Avery N. |title=Mammary number and litter size in Rodentia: the "one-half rule |journal=Proceedings of the National Academy of Sciences |date=July 1986 |volume=83 |issue=13 |page=4828-4830}}</ref> Presumably this enables females to successfully nurse litters even if some mammae fail to produce milk. Naked mole-rats break this "one-half rule"&nbsp;– field caught and lab born litters averaged 11 to 12 pups, and numbers of mammae on wild and captive females were similarly 11 to 12. Maximum litter sizes were 28 in the field and 27 in captivity, whereas the maximum number of mammae was 15. Breeding female naked mole-rats can bear and successfully rear litters that are far more numerous than their mammae because young take turns nursing from the same mammary and breeding females and pups are fed and protected by colony mates, enabling queens to concentrate their reproductive efforts on gestation and lactation.{{r|Sherman 1999|}}

====Workers====
The queen is the most active member of a colony, and she induces workers to increase their activities by repeatedly shoving them. {{r|Sherman 1991|}}<ref>{{cite journal |last1=Reeve |first1=Hudson K. |title=Queen activation of lazy workers in colonies of the eusocial naked mole-rat |journal=Nature |date=1992 |volume=358 |issue=6382 |page=147-149 |doi=10.1038/358147a0}}</ref> Smaller workers focus on acquiring food and maintaining tunnels, while the larger workers react strongly to disturbances.{{r|Sherman 1991|}}<ref>{{Cite news |last=Morelle |first=Rebecca |author-link=Rebecca Morelle |name-list-style=vanc |date=May 5, 2010 |title=Meet the 'sabre-toothed sausage' |work=BBC News |url=http://news.bbc.co.uk/2/hi/science_and_environment/10088502.stm}}</ref> As in honey bees, the workers are divided along a continuum of different worker-caste behaviors instead of being in discrete groups. Larger workers function primarily as tunnellers, expanding the large network of tunnels within the burrow system, ejecting earth excavated during tunneling onto the ground surface, and as [[soldier]]s, protecting the group from outside [[predation|predators]]. Smaller workers perform colony maintenance tasks such as foraging, nest building, and pup care.{{r|Sherman 1991|}}<ref>{{Cite journal |vauthors=Jarvis JU |year=1981 |title=Eusociality in a Mammal: Cooperative Breeding in Naked Mole-Rat Colonies |journal=Science |volume=212 |issue=4494 |pages=571–573 |bibcode=1981Sci...212..571J |doi=10.1126/science.7209555 |jstor=1686202 |pmid=7209555 |s2cid=880054}}</ref> Workers that find new food sources (tubers) in their vast subterranean burrow systems give a special vocalization on their way back to the nest and wave the food around once they get there. Recruits find the new site by following an odour trail left by the initial scout -- a behavior somewhat analogous to trail deposition and following by ants and termites.<ref>{{cite journal |last1=Judd |first1=Timothy M. |last2=Sherman |first2=Paul W. |title=Naked mole-rats recruit colony mates to food sources |journal=Animal Behaviour |date=November 1996 |volume=52 |issue=5 |page=957-969 |doi=10.1006/anbe.1996.0244|doi-access=free }}</ref>

====Dispersers====
[[Inbreeding]] is common among naked mole-rats within a colony<ref name="Reeve">{{cite journal |last1=Reeve |first1=Hudson K. |last2=Westneat |first2=David F. |last3=Noon |first3=W. A. |last4=Sherman |first4=Paul W. |last5=Aquadro |first5=Charles F. |date=April 1990 |title=DNA "fingerprinting" reveals high levels of inbreeding in colonies of the eusocial naked mole-rat |journal=Proceedings of the National Academy of Sciences |volume=87 |issue=7 |publisher=National Library of Medicine|doi=10.1073/pnas.87.7.2496|pmc=53716 }}</ref> This results in colony members being extremely closely related, which in turn favors nepotism among non-breeders toward siblings. However, prolonged inbreeding is usually associated with lower [[Fitness (biology)|fitness]].<ref>{{Cite journal |last=Bengtsson |first=B.O. |date=August 1978 |title=Avoiding inbreeding: at what cost? |journal=Journal of Theoretical Biology |volume=73 |issue=3 |pages=439–444 |bibcode=1978JThBi..73..439B |doi=10.1016/0022-5193(78)90151-0 |pmid=692150}}</ref> The discovery of male and female dispersers has revealed that there is a mechanism of inter-colony outbreeding.<ref>{{Cite journal |last=Braude |first=Stanton |date=January 2000 |title=Dispersal and new colony formation in wild naked mole-rats:evidence against inbreeding as the system of mating|journal=Behavioral Ecology |volume=11 |issue=1 |pages=7-12 |doi=10.1093/beheco/11.1.7}}</ref> Dispersers are morphologically, physiologically and behaviorally distinct from colony members and actively seek to leave their burrow when an escape opportunity presents itself.<ref name=":0">{{Cite journal |last1=Bromham |first1=Lindell |last2=Harvey |first2=Paul H |date=September 1996 |title=Behavioural ecology: Naked mole-rats on the move |journal=Current Biology |volume=6 |issue=9 |pages=1082–1083 |doi=10.1016/S0960-9822(02)70671-4 |pmid=8805352 |doi-access=free|bibcode=1996CBio....6.1082B }}</ref> These individuals are equipped with generous fat reserves for their journey.<ref name=":0" /> Though they possess high levels of [[luteinizing hormone]], dispersers are only interested in mating with individuals from foreign colonies rather than their own colony's queen.<ref name=":0" /> They also show little interest in working cooperatively with colony members in their natal burrow.<ref name=":0" /> Hence, disperser morphs are well-prepared to promote the establishment of new, initially outbred colonies, before cycles of inbreeding resume.

====Colonies====
Colonies average 75-80 individuals, but may contain more than 300, and their tunnel systems can stretch 3 to 5 kilometres (2–3&nbsp;mi) in cumulative length.{{r|Sherman 1991}}<ref>{{Cite book |last=Dawkins |first=Richard |url=https://archive.org/details/selfishgene00dawkrich |title=The Selfish Gene |publisher=Oxford University Press |year=2006 |isbn=978-0-19-286092-7 |edition=30th anniversary |url-access=registration |name-list-style=vanc |orig-year=1976}}</ref>

Laboratory colonies are xenophobic, and will attack and kill invaders from different colonies.{{r|Sherman 1991|}} Likewise, wild colonies sometimes expand their territories by invading neighboring colonies. Invaders may kidnap small pups and incorporate them into their own colony's workforce, an intriguing convergence with the behavior of slave-making ants.<ref>{{cite journal |last1=Braude |first1=Stan |last2=Hess |first2=J. |last3=Ingram |first3=C. |title=Inter-colony invasion between wild naked mole-rat colonies |journal=Journal of Zoology |date=September 2020 |volume=313 |issue=1 |page=37-42 |doi=10.1111/jzo.12834}}</ref> 

===Female mate choice===
In lab experiments, reproductively active female naked mole rats tended to associate with unfamiliar males (usually non-kin) when given a choice, whereas reproductively inactive females did not discriminate.<ref name="pmid10584337">{{Cite journal |vauthors=Clarke FM, Faulkes CG |date=October 1999 |title=Kin discrimination and female mate choice in the naked mole-rat Heterocephalus glaber |journal=Proceedings. Biological Sciences |volume=266 |issue=1432 |pages=1995–2002 |doi=10.1098/rspb.1999.0877 |pmc=1690316 |pmid=10584337}}</ref> The preference of queens for unfamiliar males likely is an adaptation to reduce inbreeding; however, within established colonies queens rarely have opportunities to express such preferences. Evolutionarily, outbreeding may be preferred because it reduces the likelihood of expressing deleterious recessive alleles,<ref name="pmid19834483">{{Cite journal |vauthors=Charlesworth D, Willis JH |date=November 2009 |title=The genetics of inbreeding depression |journal=Nature Reviews. Genetics |volume=10 |issue=11 |pages=783–96 |doi=10.1038/nrg2664 |pmid=19834483 |s2cid=771357}}</ref> whereas inbreeding results in closer genetic relationships among naked mole-rat families, favoring self-sacrificial and nepotistic behaviors.{{r|Reeve|}}

===Diet===
[[File:Naked Mole Rat Eating.jpg|thumb|A captive naked mole-rat eating]]

Naked mole-rats feed primarily on very large [[tuber]]s (weighing as much as a thousand times the body weight of a typical mole-rat) that they find deep underground through their mining operations. A single tuber can provide a colony with a long-term source of food—lasting for months, or even years, as they eat the inside but leave the outside, allowing the tuber to regenerate.{{r|Sherman 1991|}} [[Symbiosis|Symbiotic]] [[bacteria]] in the mole-rats' intestines ferment the fibres, allowing otherwise indigestible cellulose to be turned into volatile [[fatty acid]]s.<ref>{{cite journal |title=Unraveling the gut microbiome of the long-lived naked mole-rat |journal=Nature |date=29 August 2017 |volume=7 |issue=1 |page=9590 |doi=10.1038/s41598-017-10287-0 |pmid=28852094 |pmc=5575099 |bibcode=2017NatSR...7.9590D |last1=Debebe |first1=Tewodros |last2=Biagi |first2=Elena |last3=Soverini |first3=Matteo |last4=Holtze |first4=Susanne |last5=Hildebrandt |first5=Thomas Bernd |last6=Birkemeyer |first6=Claudia |last7=Wyohannis |first7=Dereje |last8=Lemma |first8=Alemayehu |last9=Brigidi |first9=Patrizia |last10=Savkovic |first10=Vulk |last11=König |first11=Brigitte |last12=Candela |first12=Marco |last13=Birkenmeier |first13=Gerd }}</ref>

Naked mole-rats sometimes also [[coprophagia|eat their own feces]]. This behavior not only nourishes pups post-weaning but also is part of their eusocial behavior: a mechanism of sharing and assessing hormones from the queen.<ref>{{Cite journal |last=Reardon |first=Sara |date=20 October 2015 |title=Poo turns naked mole rats into better babysitters |journal=Nature |doi=10.1038/nature.2015.18606 |s2cid=181362727}}</ref>

===Predators===
Naked mole rats are primarily preyed upon by snakes—especially the [[Rufous beaked snake]] and [[Kenyan sand boa]]—as well as honey badgers and various [[Bird of prey|raptors]]. They are at their most vulnerable when "volcanoing" (ejecting soil to the surface).{{r|Sherman 1991|}}<ref>{{Cite book |url=https://books.google.com/books?id=B_07noCPc4kC&q=mammals+of+africa&pg=PA670 |title=Mammals of Africa, Volume III |date=February 2013 |publisher=Bloomsbury Natural History |isbn=9781408122570 |page=670}}</ref>

==Conservation status==
Naked mole-rats are not threatened. They are widespread, numerous and, being subterranean, essentially unnoticeable in the drier regions of [[East Africa]] (except for their small "volcanoes" of ejected earth).<ref>[[IUCN|International Union for Conservation of Nature]] Red List: Heterocephalus Glaber listed as "least concern".</ref>

==''The Photo Ark''==
A naked mole-rat living at the Lincoln Children's Zoo was the first animal to be photographed for the [[National Geographic]] project, ''[[The Photo Ark]]'', which has the goal of photographing all species living in zoos and wildlife sanctuaries around the globe in order to inspire action to save wildlife.<ref name="Reader">{{Cite web |last=Biga |first=Leo Adam |date=April 10, 2018 |title=Nature photographer Joel Sartore taking cue from Noah with his National Geographic Photo Ark |url=https://thereader.com/news/environment/nature-photographer-joel-sartore-taking-cue-from-noah-with-h/ |url-status=live |archive-url=https://archive.today/20180616201712/https://thereader.com/news/environment/nature-photographer-joel-sartore-taking-cue-from-noah-with-h/ |archive-date=June 16, 2018 |access-date=June 16, 2018 |website=Thereader.com |publisher=The Reader}}</ref>

==References==
{{Reflist|refs=
<ref name="Landry">{{Cite journal |last1=Landry |first1=Stuart O. |name-list-style=vanc |date=1957 |title=The interrelationships of the New and Old World hystricomorph rodents |journal=University of California Publications in Zoology |volume=56 |pages=1–118 }}</ref>
<ref name="Ruppell1842">{{Cite journal |last=Rüppell |first=Eduard |name-list-style=vanc |date=1845 |title=Säugethiere aus der Ordnung der Nager, beobachtet im nordöstlichen Africa |url=https://www.biodiversitylibrary.org/page/45886762 |journal=Museum Senckenbergianum: Abhandlungen aus dem Gebiete der Beschreibenden Naturgeschichte |volume=3 |pages=99–101 |orig-year=1842}}</ref>
}}

==Further reading==
{{Refbegin}}
* {{Cite web |last=Ciszek |first=Deborah |year=1999 |title=''Heterocephalus glaber'', naked mole rat |url=http://animaldiversity.ummz.umich.edu/site/accounts/information/Heterocephalus_glaber.html |access-date=22 January 2010 |publisher=Animal Diversity Web }}
* {{Cite web |title=Heterocephalus glaber: Cooperation is Key |url=http://www.brookfieldzoo.org/pagegen/htm/fix/fg/fg_body.asp?sAnimal=Naked+mole-rat |url-status=dead |archive-url=https://web.archive.org/web/20101206175341/http://www.brookfieldzoo.org/pagegen/htm/fix/fg/fg_body.asp?sAnimal=Naked+mole-rat |archive-date=6 December 2010 |access-date=22 January 2010 |publisher=Brookfield Zoo }}
* {{Cite web |title=Naked Mole Rat |url=https://www.czs.org/Brookfield-ZOO/Zoo-Animals/Fragile-Desert/Naked-Mole-Rat |access-date=26 April 2017 |publisher=Chicago Zoological Society }}
* {{Cite web |last=Baskauf |first=Steve |year=2003 |title=Naked mole rat (''Heterocephalus glaber'') images |url=http://www.cas.vanderbilt.edu/bioimages/animals/mammalia/naked-mole-rat.htm |access-date=22 January 2010 |publisher=Bioimages at [[Vanderbilt University]] |archive-date=15 January 2009 |archive-url=https://web.archive.org/web/20090115042214/http://www.cas.vanderbilt.edu/bioimages/animals/mammalia/naked-mole-rat.htm |url-status=dead }}
* {{Cite web |last=Bryner |first=Jeanna |date=October 2006 |title=Naked Mole-rats Hold Clues to Human Aging |url=http://www.livescience.com/humanbiology/061009_aging_rats.html |access-date=22 January 2010 |publisher=LiveScience }}
* {{Cite journal |last1=Sherman |first1=Paul W. |last2=Jarvis |first2=Jennifer U. M. |name-list-style=vanc |date=November 2002 |title=Extraordinary life spans of naked mole-rats (''Heterocephalus glaber'') |journal=Journal of Zoology |volume=258 |issue=3 |pages=307–311 |doi=10.1017/S0952836902001437}}
* {{Cite journal |last1=Shuster |first1=Gabriela |last2=Sherman |first2=P. W. |name-list-style=vanc |year=1998 |title=Tool use by naked mole-rats |journal=Animal Cognition |volume=1 |issue=1 |pages=71–74 |doi=10.1007/s100710050009 |s2cid=11671840}}
* {{Cite web |last=Choi |first=Charles Q. |name-list-style=vanc |date=January 2008 |title=Strange Creature Immune to Pain |url=http://www.livescience.com/animals/080128-mole-rat-pain.html |access-date=22 January 2010 |publisher=LiveScience }}
* {{Cite web |title=Small Mammals (with a naked mole-rat webcam) |url=http://nationalzoo.si.edu/Animals/SmallMammals/default.cfm?cam=NMR |access-date=22 January 2010 |publisher=Smithsonian National Zoological Park }}
{{Refend}}

==External links==
{{Commons|Heterocephalus glaber|Naked Mole Rat}}
{{Wikispecies|Heterocephalus glaber|Naked Mole Rat}}
* {{UCSC genomes|hetGla2}}

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[[Category:Phiomorpha]]
[[Category:Coprophagous animals]]
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[[Category:Fauna of the Horn of Africa]]
[[Category:Fauna of Kenya]]
[[Category:Mammals described in 1842]]
[[Category:Negligibly senescent organisms]]
[[Category:Rodents of Africa]]
[[Category:Taxa named by Eduard Rüppell]]