Editing Tenrec (section)

==Characteristics==

Tenrecs are small mammals of variable body form. The smallest species are the size of shrews, with a body length of around {{convert |4.5 |cm |abbr=on}}, and weighing just {{convert |5 |g |abbr=on}}, while the largest, the common or [[tailless tenrec]], is {{convert |25 |to |39 |cm |abbr=on}} in length, and can weigh over {{convert |1 |kg}}.<ref name="EoM">{{cite book |editor=Macdonald, D. |author=Nicholl, Martin |year=1984 |title=The Encyclopedia of Mammals |publisher=Facts on File |location=New York |pages=[https://archive.org/details/encyclopediaofma00mals_0/page/744 744–747] |isbn=978-0-87196-871-5 |url-access=registration |url=https://archive.org/details/encyclopediaofma00mals_0/page/744}}</ref> Although they may resemble shrews, hedgehogs, or opossums, they are not closely related to any of these groups, their closest relatives being the [[otter shrew]]s, and after that other African insectivorous mammals including [[golden mole]]s and [[elephant shrew]]s. The common ancestry of these animals, which are classified together in the [[clade]] [[Afrotheria]], was not recognized until the late 1990s.<ref>{{Cite journal | last1=Stanhope | first1=M.J. | last2=Waddell | first2=V.G. | last3=Madsen | first3=O. | last4=de Jong | first4=W |author5=Hedges, S.B. |author6=Cleven, G.C. |author7=Kao, D. |author8=Springer, M.S. |display-authors=3 | title=Molecular evidence for multiple origins of Insectivora and for a new order of endemic African insectivore mammals | journal=PNAS | year=1998 | volume=95 | issue=17 | pages=9967–9972 | doi=10.1073/pnas.95.17.9967 | pmid=9707584 | pmc=21445 | bibcode=1998PNAS...95.9967S | doi-access=free }}</ref> Continuing work on the molecular<ref>{{Cite journal | title=Molecules consolidate the placental mammal tree | journal=Trends Ecol Evol | year=2004 | volume=19 | issue=8 | pages=430–438
 | pmid=16701301 |author=Springer, M.S.; Stanhope, M.J.; Madsen, O.; de Jong, W.W. | doi=10.1016/j.tree.2004.05.006 | s2cid=1508898 }}</ref><ref>{{Cite journal | year=2004 | title=Cross-species chromosome painting in the golden mole and elephant-shrew: support for the mammalian clades Afrotheria and Afroinsectiphillia but not Afroinsectivora | journal=[[Proceedings of the Royal Society B]] | volume=271 | issue=1547 | pages=1477–1484  | doi=10.1098/rspb.2004.2754
 | author=Robinson, T. J.; Fu, B.; Ferguson-Smith, M. A.; Yang, F. | pmid=15306319 | pmc=1691750 }}</ref> and morphological<ref>{{Cite journal  | year=2009 | title=The new framework for understanding placental mammal evolution
 | journal=BioEssays | volume=31 | issue=8 | pages=853–864 | pmid=19582725 |author1=Asher, R.J. |author2=Bennet, N. |author3=Lehmann, T. | doi=10.1002/bies.200900053 | s2cid=46339675  | doi-access=free}}</ref><ref>{{Cite journal
 | title=Early tertiary mammals from North Africa reinforce the molecular Afrotheria clade | journal=[[Proceedings of the Royal Society B]] | year=2007 | volume=274 | issue=1614 | pages=1159–1166 | doi=10.1098/rspb.2006.0229  | last1=Tabuce | first1=R. | last2=Marivaux | first2=L. | last3=Adaci | first3=M. | last4=Bensalah | first4=M. | last5=Hartenberger |first5=J.-L. |first6=M. |last6=Mahboubi |first7=F. |last7=Mebrouk |first8=P. |last8=Tafforeau |first9=J.-J. |last9=Jaeger |display-authors=3 | pmid=17329227 | pmc=2189562}}</ref><ref>{{Cite journal | last=Seiffert | first=E. | title=A new estimate of afrotherian phylogeny based on simultaneous analysis of genomic, morphological, and fossil evidence | journal=BMC Evolutionary Biology | year=2007 | volume=7 | issue=224 | page=13 | doi=10.1186/1471-2148-7-224 | pmid=17999766 | pmc=2248600 | doi-access=free | bibcode=2007BMCEE...7..224S }}</ref><ref>{{Cite journal | title=Thoracolumbar vertebral number: the first skeletal synapomorphy for afrotherian mammals | journal=Syst Biodivers | year=2007 | volume=5 | issue=1 | pages=1–17 | doi=10.1017/S1477200006002258 | author=Sanchez-Villagra, M. R., Narita, Y. and Kuratani, S. | bibcode=2007SyBio...5Q...1S | s2cid=85675984 }}</ref> diversity of afrotherian mammals has provided ever increasing support for their common ancestry.

Tenrecs are among the few terrestrial mammals that [[Animal echolocation |echolocate]].<ref>{{cite journal |last=Gould |first=Edwin |title=Evidence for echolocation in the Tenrecidae of Madagascar |journal=Proceedings of the American Philosophical Society |volume=109 |issue=6 |year=1965 |pages=352–360 |jstor=986137 }}</ref> 
Unusual among [[placental mammal]]s, the [[rectum]] and [[genitourinary system |urogenital tract]]s of tenrecs share a common opening, or [[cloaca]] which is a feature more commonly seen in [[bird]]s, [[reptile]]s, and [[amphibian]]s. They have a low [[body temperature]], sufficiently low  that they do not require a [[scrotum]] to cool their [[sperm]] as do most other mammals.<ref name="EoM" /><ref>{{Cite news |last=Yin |first=Steph |url=https://www.nytimes.com/2018/06/29/science/descending-testicles-evolution.html?rref=collection/sectioncollection/science&action=click&contentCollection=science&region=rank&module=package&version=highlights&contentPlacement=8&pgtype=sectionfront |title=The Evolutionary Origin of Descending Testicles |work=The New York Times |date=29 June 2018 |access-date=2018-07-10  }}</ref>

All species appear to be at least somewhat [[omnivore |omnivorous]], with [[invertebrate]]s forming the largest part of their diets. One species, ''Microgale mergulus'', is [[semiaquatic]] (similar to the lifestyle of their closest relatives, the otter shrews).<ref>{{Cite book |author1=Benstead, J. P. |author2=Olson, L. E. | chapter=''Limnogale mergulus'', web-footed tenrec or aquatic tenrec | year=2003 | pages=1267–1273 |editor1=S. M. Goodman |editor2=J. P. Benstead | publisher=University of Chicago Press | location=Chicago | isbn=978-0-226-30307-9 | title=The natural history of Madagascar
}}</ref> All of the species, semiaquatic or not, appear to have evolved from a single, common ancestor with the otter shrews comprising the next, most-closely related mammalian species.<ref>{{Cite book | chapter=Phylogeny and biogeography of tenrecs | title=The Natural History of Madagascar |editor1=Goodman, S. M. |editor2=Benstead J. P. | location=Chicago | publisher=Chicago University Press | year=2003 | pages=1235–1242 | isbn=978-0-226-30307-9 |author1=Olson, L. E. |author2=Goodman, S. M. }}</ref><ref>{{Cite journal | title=Molecular phylogeny and divergence times of Malagasy tenrecs: influence of data partitioning and taxon sampling on dating analyses | journal=BMC Evolutionary Biology | year=2008 | volume=8 | doi=10.1186/1471-2148-8-102 | author1=Poux, C. |author2=Madsen, O. |author3=Glos, J. |author4=de Jong, W.W. |author5=Vences, M. | issue=1 | page=102 | pmid=18377639  | pmc=2330147 | doi-access=free | bibcode=2008BMCEE...8..102P }}</ref> While the fossil record of tenrecs is scarce, at least some specimens from the early [[Miocene]] of Kenya show close affinities to living species from Madagascar,<ref>{{Cite journal | title=Tenrec phylogeny and the noninvasive extraction of nuclear DNA | journal=Systematic Biology | year=2006 | volume=55 | issue=2 | pages=181–194 | doi=10.1080/10635150500433649  |author1=Asher, R.J. |author2=Hofreiter, M. | pmid=16522569 | doi-access=free }}</ref> such as ''Geogale aurita''.

Most species are [[nocturnal]] and have poor eyesight. Their other senses are well developed, however and they have especially sensitive [[vibrissa |whiskers]]. As with many of their other features, the [[dentition |dental formula]] of tenrecs varies greatly between species; they can have from 32 to 42 teeth in total. Unusual for mammals, the permanent dentition in tenrecs tends not to completely erupt until well after adult body size has been reached.<ref>{{Cite journal
 | year=2008 | title=Dental eruption in afrotherian mammals | journal=BMC Biology | volume=6 | doi=10.1186/1741-7007-6-14 | author1=Asher, R. J.  |author2=Lehmann, T. | page=14 | pmid=18366669  | pmc=2292681 | doi-access=free }}</ref> This is one of several anatomical features shared by elephants, [[hyrax]]es, [[sengi]]s, and [[golden mole]]s (but apparently not [[aardvark]]s), consistent with their descent from a common ancestor.{{cn|date=September 2023}}

Tenrecs have a [[gestation]] period of 50 to 64 days, and give birth to a number of relatively undeveloped young. While the [[Giant Otter Shrew |otter shrew]]s have just two young per litter, the tailless tenrec can have as many as 32, and females possess up to 29 [[teat]]s, more than any other mammal.<ref name="EoM"/> Some tenrec species are social, living in multigenerational family groups with over a dozen individuals.{{cn|date=September 2023}}