Sylvilagus insonusOmilteme cottontail

Ge­o­graphic Range

Omil­teme cot­ton­tails (Sylvi­la­gus in­sonus) have a very lim­ited dis­tri­b­u­tion. They are found in the Sierra Madre del Sur, lo­cated near the small town of Omil­teme, Guer­rero, Mex­ico. Omil­teme cot­ton­tails are an ex­tremely rare species, with a ge­o­graphic range of less than 500 km2. They occur sym­patri­cally with Mex­i­can cot­ton­tails (Sylvi­la­gus cu­nic­u­lar­ius) and east­ern cot­ton­tails (Sylvi­la­gus flori­danus). (Cer­bal­los and Navarro, 1991; Diers­ing, 1981; Nel­son, 1904; Nel­son, 1909)

Habi­tat

Sierra Madre del Sur is a semi-iso­lated moun­tain range near the small town of Omil­teme, Guer­rero, Mex­ico. Omil­teme cot­ton­tails are re­stricted to this moun­tain range, which of­fers the humid, dense forests that they pre­fer. They live amongst dense un­der­growth, tun­nel­ing to hide move­ment and dig­ging under rocks or other ob­ject to cre­ate bur­rows. Omil­teme cot­ton­tails are re­stricted to pine and pine-oak forests in the Sierra Madre del Sur moun­tains, which have el­e­ments of tem­per­ate forests such as pine species, oaks, and alders. (Diers­ing, 1981; Nel­son, 1904; Nel­son, 1909)

  • Range elevation
    2,230 to 5, 280 m
    to ft

Phys­i­cal De­scrip­tion

Omil­teme cot­ton­tails are large rab­bits with long ears, short tails and av­er­age sized hind feet. Only three spec­i­mens have ever been col­lected, so mea­sure­ments and ob­ser­va­tions are based on a very small sam­ple size. Their ears, which are es­ti­mated to be be­tween 53 and 63.5 mm (mea­sured from notch), are dark black­ish-brown on the con­vex side with a black bor­der and tip. The dor­sal body is grey­ish-black with a mix­ture of ru­fous and black on the back and they have white ven­tral sur­faces. The tail, which is be­tween 30 and 45 mm, is red­dish-black on the dor­sal side and white on the ven­tral side. The hind feet have white tops with black soles. Omil­teme cot­ton­tails lives sym­patri­cally with Mex­i­can cot­ton­tails and east­ern cot­ton­tails, but are no­tably smaller in all mea­sure­ments.

Omil­teme cot­ton­tails have large skulls with a long palate, broad brain case, large max­il­lary and mandibu­lar tooth rows, short di­astema and in­ci­sive foram­ina, and a shal­low skull depth. Omil­teme cot­ton­tails have a den­tal for­mula of: in­cisors 2/1, ca­nines 0/0, pre­mo­lars 3/2 and mo­lars 3/3, to­tal­ing 28.

Of the three col­lected spec­i­mens, mea­sure­ments were taken of two. The two spec­i­mens had cra­nial and ex­ter­nal mea­sure­ments of: mean mass, 2.58 kg; mean body length (in­clud­ing the head but ex­clud­ing the tail), 425 mm; mean length of the tail, 43 mm; mean length of hind foot, 94.5 mm; mean di­am­e­ter of bul­lae, 9.1 mm; mean in­teror­bital breadth, 17.6 mm; mean basi­lar length, 58.1 mm. (Diers­ing, 1981; Nel­son, 1904; Nel­son, 1909; Nowak, 1999; cer­vantes and lorenzo, 1997)

  • Sexual Dimorphism
  • sexes alike
  • Range mass
    2.46 to 2.7 kg
    5.42 to 5.95 lb
  • Range length
    430 to 440 mm
    16.93 to 17.32 in

Re­pro­duc­tion

Noth­ing is known about Omil­teme cot­ton­tail mat­ing sys­tems, al­though they are thought to be sim­i­lar to other cot­ton­tail species, where males and fe­males meet with mul­ti­ple mates. (Hall, 1981; Lump­kin and Sei­den­sticker, 2011; Nowak, 1999)

No re­ports of Omil­teme cot­ton­tail re­pro­duc­tion exist. All fe­male rab­bits are thought to be in­duced ovu­la­tors, mean­ing they need stim­u­la­tion of courtship and cop­u­la­tion to ovu­late. Most Sylvi­la­gus species have a ges­ta­tion length of 28 to 30 days, gen­er­ally with al­tri­cial young. Cot­ton­tails con­struct un­der­ground nests that they line with veg­e­ta­tion and shed fur. Breed­ing is sea­sonal, even for species liv­ing near the equa­tor, gen­er­ally from March to Au­gust. (Hall, 1981; Lump­kin and Sei­den­sticker, 2011; Nowak, 1999)

  • Breeding interval
    Breeding interval in Omilteme cottontails is not known.
  • Breeding season
    The breeding season of Omilteme cottontails is not known, but is likely to be from March to August.

No re­ports of Omil­teme cot­ton­tail re­pro­duc­tion exist. Cot­ton­tails con­struct nests, gen­er­ally un­der­ground, lined with veg­e­ta­tion and shed fur and nurse their young until they be­come in­de­pen­dent at about 2 weeks old. Young cot­ton­tails are gen­er­ally born in an al­tri­cial state. (Hall, 1981; Lump­kin and Sei­den­sticker, 2011; Nowak, 1999)

  • Parental Investment
  • altricial
  • female parental care
  • pre-fertilization
    • provisioning
    • protecting
      • female
  • pre-hatching/birth
    • provisioning
      • female
    • protecting
      • female
  • pre-weaning/fledging
    • provisioning
      • female
    • protecting
      • female

Lifes­pan/Longevity

The lifes­pan of Omil­teme cot­ton­tails is not doc­u­mented. It may be as­sumes that lifes­pan is sim­i­lar to the closely re­lated species Mex­i­can cot­ton­tails and east­ern cot­ton­tails, which are short lived. There is a gen­eral re­la­tion­ship among body size and longevity, as larger species gen­er­ally live longer than smaller ones. As­sum­ing this re­la­tion­ship holds, Omil­teme cot­ton­tails are larger than east­ern cot­ton­tails, so their lifes­pan may sur­pass the av­er­age age of east­ern cot­ton­tails, which is 3 years. Omil­teme cot­ton­tails are smaller than the larger Mex­i­can cot­ton­tails, which live up to 5 years. Most cot­ton­tail species do not live past their fifth year in the wild. (Cer­vantes, et al., 1992; Diers­ing, 1981; Lump­kin and Sei­den­sticker, 2011; Nel­son, 1909)

Be­hav­ior

Lit­tle is doc­u­mented about Omil­teme cot­ton­tail be­hav­ior. They are noc­tur­nal and may be ac­tive at dusk and dawn as well. Most cot­ton­tails are aso­cial and soli­tary, only com­ing to­gether dur­ing the breed­ing sea­son or rare ag­gre­ga­tions at feed­ing sites. (Cer­vantes, et al., 1992; Lump­kin and Sei­den­sticker, 2011; Nel­son, 1904; Nel­son, 1909; Nowak, 1999)

Home Range

Noth­ing is known about the home range of this species. (Cer­bal­los and Navarro, 1991)

Com­mu­ni­ca­tion and Per­cep­tion

As with most as­pects of its bi­ol­ogy, there is lit­tle known about spe­cific Omil­teme cot­ton­tail com­mu­ni­ca­tion. How­ever, other cot­ton­tail species have su­perb ol­fac­tory, hear­ing, and vi­sual sys­tems. They often emit dis­tress calls, squeal­ing dur­ing cop­u­la­tion and grunt­ing if an in­truder is in sight. (Cer­vantes, et al., 1992; Hall, 1981; Lump­kin and Sei­den­sticker, 2011)

Food Habits

Omil­teme cot­ton­tails are her­bi­vores. They may eat sim­i­lar foods to the sym­patric Mex­i­can cot­ton­tails, which eat clumped grasses in­clud­ing Stipa ichu, Muh­len­ber­gia macroura and Fes­tuca am­plis­sima. Pre­ferred veg­e­ta­tion is ten­der grass shoots, cor­tices of shrubs, cul­ti­vated plants (such as oats, bar­ley and maize) and young leaves of forbes. Omil­teme cot­ton­tails may pre­fer slightly dif­fer­ent foods, if there is eco­log­i­cal char­ac­ter dis­place­ment in these sim­i­lar, sym­patric species. They also en­gage in co­prophagy. (Cer­vantes, et al., 1992; Diers­ing and Wil­son, 1980; Lump­kin and Sei­den­sticker, 2011; Luna and Bous­quets, 1993; Nel­son, 1909)

  • Plant Foods
  • leaves
  • wood, bark, or stems
  • flowers
  • Other Foods
  • dung

Pre­da­tion

Hu­mans are the only recorded preda­tors of Omil­teme cot­ton­tails. Pumas (Puma con­color), jaguars (Pan­thera onca), gray wolves (Canis lupus), coy­otes (Canis la­trans) and zone-tailed hawks (Buteo al­bono­ta­tus) fre­quent the Sierra Madre del Sur re­gion, and are likely preda­tors of Omil­teme cot­ton­tails. Like other rab­bits, they are cryp­ti­cally col­ored and can flee quickly for short dis­tances. (Cer­vantes, et al., 1992; Chap­man and Ce­bal­los, 2013; Mon­roy-vilchis, 2013; World Wildlife Fund, 2013; cer­vantes and lorenzo, 1997)

  • Anti-predator Adaptations
  • cryptic

Ecosys­tem Roles

Omil­teme cot­ton­tails may im­pact their habi­tat through the plants they eat. They are also a food source for many preda­tors (Hall 1981; Lump­kin and Sei­den­sticker 2011). (Hall, 1981; Lump­kin and Sei­den­sticker, 2011)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

Omil­teme cot­ton­tails are hunted by hu­mans for their fur and for a food source and are now con­sid­ered one of the most en­dan­gered rab­bits in the world.

  • Positive Impacts
  • food
  • body parts are source of valuable material

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

There are no known neg­a­tive im­pacts of Omil­teme cot­ton­tails on hu­mans.

Con­ser­va­tion Sta­tus

Omil­teme cot­ton­tails are ex­tremely rare due to their frag­mented habi­tat and ex­tremely re­stricted range in Sierra Madre del Sur, Guer­rero, Mex­ico, which is less than 500 square kilo­me­ters in size. The last re­ported sight­ing of an Omil­teme cot­ton­tail in the wild was in the early 1900’s; how­ever, there was a pos­si­ble sight­ing in 1991. This species was listed as ex­tinct in 1990, en­dan­gered in 1994, and crit­i­cally en­dan­gered in 1996. How­ever, they are cur­rently listed under the IUCN Red List Cat­e­gory as en­dan­gered, and crit­i­cally en­dan­gered in the Mex­i­can Of­fi­cial Norm, due to the re­cov­ery of a skin in 1998. Fol­low­ing the find­ing of this skin, a sur­vey within the Omil­teme cot­ton­tail range took place, ap­prox­i­mately 52 days, which re­sulted in no Omil­teme cot­ton­tail sight­ings.

Many sources con­sider the Omil­teme cot­ton­tail to be ex­tinct. De­for­esta­tion of the Omil­teme cot­ton­tail habi­tat is seen as the main fac­tor for their en­dan­ger­ment, or pos­si­ble ex­tinc­tion. Pre­vi­ously, Sierra Madre del Sur was ex­ten­sively logged, caus­ing wide scale habi­tat frag­men­ta­tion. Poach­ing is also a pre­sent con­cern. Though a nat­ural re­serve area, re­ferred to as the Omil­temi State Eco­log­i­cal Park, cur­rently cov­ers the Omil­teme cot­ton­tail habi­tat, il­le­gal hunt­ing of the Omil­teme cot­ton­tail is still a con­cern. (Cer­vantes, et al., 1992; Cer­vantes, et al., 2004; Jimenex, et al., 1993; Nel­son, 1904; Nel­son, 1909; Romero Malpica and Rangel Cordero, 2013; cer­vantes and lorenzo, 1997)

Other Com­ments

Omil­teme cot­ton­tails are con­sid­ered the rarest and least un­der­stood of rab­bits. There are only three mu­seum spec­i­mens of this species and the last ob­ser­va­tion of an Omil­teme cot­ton­tail was in 1998 by a hunter. The phy­lo­ge­netic re­la­tion­ships of S. in­sonus are un­known. Tapeti were once con­sid­ered to be the clos­est sis­ter species of S. in­sonus based on mor­phol­ogy and were put into the sub­genus Tapeti. How­ever, they were trans­ferred to the sub­genus Sylvi­la­gus after ge­netic com­par­i­son and are now con­sid­ered to be more closely re­lated to east­ern cot­ton­tails and Mex­i­can cot­ton­tails. As a re­sult of this tax­o­nomic con­fu­sion, Omil­teme cot­ton­tails have been re-clas­si­fied three times. Orig­i­nally this species was re­ferred to as Tapeti in­sonus, then re­named to Lepus in­sonus and is cur­rently known as Sylvi­la­gus in­sonus. (Cer­bal­los and Navarro, 1991; Diers­ing, 1981; Her­shkovitz, 1950; Lump­kin and Sei­den­sticker, 2011; Nel­son, 1909; Tate, 1993; cer­vantes and lorenzo, 1997)

Con­trib­u­tors

Chris­tine Quir­ing (au­thor), Uni­ver­sity of Man­i­toba, Jane Wa­ter­man (ed­i­tor), Uni­ver­sity of Man­i­toba, Tanya Dewey (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

acoustic

uses sound to communicate

altricial

young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

coprophage

an animal that mainly eats the dung of other animals

crepuscular

active at dawn and dusk

cryptic

having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

female parental care

parental care is carried out by females

folivore

an animal that mainly eats leaves.

food

A substance that provides both nutrients and energy to a living thing.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

herbivore

An animal that eats mainly plants or parts of plants.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

mountains

This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

polygynous

having more than one female as a mate at one time

saltatorial

specialized for leaping or bounding locomotion; jumps or hops.

seasonal breeding

breeding is confined to a particular season

sedentary

remains in the same area

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

solitary

lives alone

tactile

uses touch to communicate

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

visual

uses sight to communicate

viviparous

reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

Ref­er­ences

Cer­bal­los, G., D. Navarro. 1991. Di­ver­sity and con­ser­va­tion of mex­i­can mam­mals. Pp. 167-198 in M Mares, D Schmidly, eds. Di­ver­sity and Con­ser­va­tion of Mex­i­can Mam­mals. In: Latin Amer­i­can Mam­mal­ogy, Vol. 1, 1 Edi­tion. Ok­la­homa: Uni­ver­sity of Ok­la­homa Press.

Cer­vantes, F., C. Lorenzo, F. Gon­za­lex-Cozatl. 2004. The Omil­teme rab­bit (Syli­bi­la­gus in­sonus) is not ex­tinct. Bi­ol­ogy of Mam­mals, 69: 61-64.

Cer­vantes, F., C. Lorenzo, J. Var­gas, T. Holmes. 1992. Sylvi­la­gus cu­nic­u­lar­ius. jour­nal of mam­mol­ogy, 412: 1-2.

Chap­man, J., G. Ce­bal­los. 2013. "IUCN" (On-line). The cot­ton­tails. Ac­cessed Oc­to­ber 11, 2013 at www.​iucnredlist.​org.

Diers­ing, V. 1981. Sys­tem­atic sta­tus of Sylvi­la­gus brasilien­sis and S. in­sonus from North Amer­ica. Jour­nal of Mam­mol­ogy, 62: 539-556.

Diers­ing, V., D. Wil­son. 1980. Dis­tri­b­u­tion and sys­tem­at­ics of the rab­bits (Sylvi­la­gus) of west-cen­tral Mex­ico. Jour­nal of Zo­ol­ogy, 297: 1-34.

Hall, R. 1981. Syvi­la­gus. Pp. 312 in Mam­mals of North Amer­ica, Vol. 2, 2 Edi­tion. Uni­ver­sity of Kansas, New York: John Wiley and Sons Inc.

Her­shkovitz, P. 1950. Sylvi­la­gus brasilien­sis sanc­tae­mar­tae. Pro­ceed­ings of the United States Na­tional Mu­seum, 100: 353.

Jimenex, A., I. Pa­ni­agua, J. Gomez. 1993. Mamf­feros in His­to­ria Nat­ural del Par­que Eco­logico Es­tatal Omil­temi, Chilpancingo, Guer­rero, Mex­ico. Mex­ico City: Comi­sion Na­cional para el Conocimiento y Uso de la Bio­di­ver­si­dad y Uni­ver­si­dad Na­cional Au­tonome de Mex­ico.

Lump­kin, S., J. Sei­den­sticker. 2011. Rab­bits: the an­i­mal an­swer guide. Bal­ti­more, Mary­land: The John Hop­kins Uni­ver­sity Press.

Luna, V., J. Bous­quets. 1993. His­to­ria Nat­ural del Par­que Eco­logico Es­tatal Omil­temi, Chilpancingo, Guer­rero, Mex­ico. Mex­ico City: Comi­sion No­cional para el Co­mocimiento y Uso de la Biod­ver­si­dad y Uni­ver­si­dad Na­cional Au­tonoma de Mex­ico.

Mon­roy-vilchis, O. 2013. Spa­tial model of live­stock pre­da­tion by jaguar and puma in Mex­ico: con­ser­va­tion plan­ning. Bi­ol­ogy Con­ser­va­tion, 159: 80-87.

Nel­son, E. 1904. De­scrip­tion of seven new rab­bits from Mex­ico. Pro­ce­dures of Bi­o­log­i­cal So­ci­ety, 17: 103-110.

Nel­son, E. 1909. The rab­bits of North Amer­ica. Amer­i­can Fauna, 29: 9-287.

Nowak, R. 1999. Sylvi­la­gus in­sonus. Pp. 1045-1046 in E Walker, ed. Walker's Mam­mals of the World, Vol. 2, 6 Edi­tion. Bal­ti­more: The John Hop­kins Uni­ver­sity Press.

Romero Malpica, F., H. Rangel Cordero. 2013. "IUCN Red List of Threat­ened Species" (On-line). Sylvi­la­gus in­sonus. Ac­cessed Oc­to­ber 12, 2013 at www.​iucnredlist.​org.

Tate, G. 1993. Tax­o­nomic His­tory of the Neotrop­i­cal Hares of the Genus Sylvi­la­gus, sub­genus Tapeti. New York City: The Amer­i­can Mu­seum of Nat­ural His­tory.

World Wildlife Fund, (. 2013. "

Sierra Madre Ori­en­tal and Oc­ci­den­tal pine-oak forests
" (On-line). World Wildlife Fund. Ac­cessed No­vem­ber 11, 2013 at http://​wwf.​panda.​org/​about_​our_​earth/​ecoregions/​sierramadre_​pineoak_​forests.​cfm.

cer­vantes, F., C. lorenzo. 1997. Sylvi­la­gus in­sonus. Spec, 568: 1-4.