Sciurus oculatus Peters 1863

No other information was found directly relating to S. oculatus, but other tree squirrels (Sciurus) are preyed on by a number of predatory bird and mammal species. Large raptors and arboreal carnivores, such as Bassariscus species, are also likely predators of S. oculatus.

Known Predators:

• humans (Homo sapiens)
• diurnal raptors (Falconiformes)
• Bassariscus species

Anti-predator Adaptations: cryptic

No specific studies were found that examined food habits of S. oculatus, however Best (1995) noted that some populations of S. oculatus consumed acorns and wild figs, while others rely primarily on pine nuts. Tree squirrels in general prefer foods that can be eaten quickly, are digestible, and provide high amounts of energy. Squirrels often eat animal foods as well as seeds and fruit. They drink surface water when it is available, however, in its absence they can extract enough moisture from their food with the exception of pregnant or nursing females.

Plant Foods: seeds, grains, and nuts; fruit

Foraging Behavior: stores or caches food

Primary Diet: herbivore (Frugivore , Granivore )

Tree squirrels (Sciurus) in general are host to a wide range of parasites such as botflies, fleas, ticks, mites, lice, roundworms, and tapeworms and are also vulnerable to rabies, pox, fibroma, monkeypox, and parapox viruses. The genus Enderleinellus is a parasite that is found on Sciurus oculatus and occurs exclusively on hosts of the family Sciuridae. Squirrels also disperse the seeds of plants through their seed caching behavior and via attachment to their fur.

Ecosystem Impact: disperses seeds

Commensal/Parasitic Species:

• squirrel louse (Enderleinellus longiceps)
• squirrel louse (Enderleinellus oculatus)
• botflies (Oestridae)
• fleas (Siphonaptera)
• ticks and mites (Acari)
• roundworms (Nematoda)
• tapeworms (Cestoda)

No information was found directly related to the hunting of Sciurus oculatus, but is assumed that they are hunted for food and disperse seeds like other squirrel species.

Positive Impacts: food ; body parts are source of valuable material

There are no known adverse effects of S. oculatus on humans.

Sciurus oculatus has suffered severe habitat loss through logging, burning, and clearing of forest for agriculture in Mexico. As of 1991, it was considered a "fragile" species, though, as of 1996, IUCN listed it as "Lowest Risk/Least Concern." The IUCN web page recognizes that this listing is out of date.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

No information was found directly relating to Sciurus oculatus. However, tree squirrels rely heavily on vision to perceive their environment. Their retinas contain layers of both rod and cone cells. They can see yellow, red, and green, and can also distinguish blue from green. However, they lack a tapetum which allows some animals to see better in low light. They do have yellow tinted lenses to protect them from damaging ultraviolet rays in the daylight hours. Tree squirrels also process visual information quite rapidly; one study showed they process visual information at twice the speed of an average human. Like other mammals, they also use chemosensation and touch as important modes of perception. Squirrels have whiskers on their faces and wrists to help in navigating their complex environment.

Communication Channels: visual ; acoustic ; chemical

Other Communication Modes: scent marks

Perception Channels: visual ; tactile ; acoustic ; chemical

This squirrel's name is derived from the Latin Sciurus meaning "squirrel" and oculus referring to the eye. It also goes by names black-backed, Toluca, and spectacled squirrel.

Sciurus oculatus is a squirrel species endemic to Mexico. It ranges within the Trans-Mexican neovolcanic belt and the Mexican Plateau from Morelos, Distrito Federal, Mexico, Puebla and Veracruz northward into San Luis Potosi. In the summer months, Peter's squirrels are common in Alvarez, inhabiting the low oak forest of the mountainsides. As temperatures cool, they move to nearby valleys by late October. There are three recognized subspecies within this range: S. o. oculatus, S. o. shawi, and S. o. tolucae.

Biogeographic Regions: nearctic (Native )

Sciurus oculatus prefer habitats of oak (Quercus), pine (Pinus), and fir (Abies, Pseudotsuga) forest. Populations tend to occupy different tree species depending on their location and time of year. In the summer months, some populations live in low oak trees on mountainsides in Alvarez. By late October, however, this group migrates to Veracruz and usually occupies pine forests at higher elevations or on the timbered slopes of Cofre de Perote and Mount Orizaba.

Range elevation: 1500 to 3600 m.

Average elevation: 1800 m.

Habitat Regions: temperate ; tropical ; terrestrial

Terrestrial Biomes: forest ; mountains

Other Habitat Features: urban ; suburban

No studies have determined the average lifespan for Sciurus oculatus.

Peter's squirrels are large tree squirrels with an average weight of 638 grams. They are mostly gray with white ears and a white underside. Peter’s squirrels have black tails and a 25 to 50 mm wide black stripe that extends from the back of the head to the tail. They have four pairs of mammae (one pectoral, one inguinal and two abdominal). Subspecies S. o. oculatus, S. o. tolucae, and S. o. shawi vary in total, tail, and hind foot lengths. The average total lengths for the subspecies are: S. o. oculatus 543mm, S. o. tolucae 531mm, and S. o. shawi 508mm. Average tail length of S. o. oculatus is 269 mm, S. o. tolucae is 263 mm, and S. o. shawi is 256 mm. Average hind foot length for S. o. oculatus is 73 mm, S. o. tolucae is 69 mm, and S. o. shawi is 68 mm.

Average mass: 638 g.

Range length: 530 to 560 mm.

Average length: 543 mm.

Other Physical Features: endothermic ; homoiothermic; bilateral symmetry

Sexual Dimorphism: sexes alike; male larger

No specific studies were found which examined the mating systems of Peter's squirrels. However, detailed information is available for a closely related species, eastern gray squirrels (Sciurus carolinensis). In this species, male and female squirrels communicate reproductive information through scent. Males leave their normal home range to pursue females when the females are near estrus. Males then follow females for about 5 days before she goes into estrus and attract her attention through a unique sneeze-like mating call. On the day of a female's estrus many males aggressively pursue her in a "mating chase." She then chooses a male with which to mate. After copulation, the male's semen forms a plug, in an attempt to prevent further mating. However, in as little as 20 seconds, females may remove the plug by eating or discarding it. Therefore, eastern gray squirrel females remain in estrus for about a day and may breed with several males. It is likely that the mating system of Sciurus oculatus is similar.

Mating System: polygynandrous (promiscuous)

Specific information on the reproductive behavior of Peter's squirrels is not available. However, their close relative, eastern gray squirrels (Sciurus carolinensis) are seasonal breeders; their mating activities are triggered by changes in day length and their productivity is linked strongly to food supply. A female squirrel usually produces her first litter at about a year old, unless food is scarce. In that case, they may wait until their second year to breed.

Breeding interval: Yearly, probably starting at age 2.

Breeding season: Female Sciurus oculatus have had enlarged mammae in July and August, indicating litters earlier in the season.

Average age at sexual or reproductive maturity (female): 2 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous

Information on parental investment in Peter's squirrels has not been documented. However, eastern grey squirrels (Sciurus carolinensis) depend on their mother's milk for 7 to 10 weeks and are born in strongly-built leaf nest held together by a woven framework of twigs or in tree cavities.

Parental Investment: altricial ; pre-fertilization (Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Male, Female); pre-independence (Protecting: Male, Female)

Factores de riesgo

El principal factor de riesgo es la destrucción de habitat por tala, quema para convertir el terreno en tierra de cultivo.

Parásitos

Los únicos ectoparásitos que se conocen son piojos (Enderleinellus longiceps y E. oculatus (Ferris, 1961; Kim, 1966). No se conocen endoparásitos.

Antecedentes del estado de la especie o de las poblaciones principales

El género Sciurus evolucionó en el Mioceno temprano, pero no se conocen fósiles de Sciurus oculatus.

Sciurus oculatus tiene un tamaño muy similar al de S. aureogaster, pero esta última tiene un cuerpo mucho más grueso. Genéticamente es más cercana a S. niger que a S. carolinensis.
Sciurus oculatus es una ardilla grande arborícola. El dorso tiene un pelaje color gris o bien presenta una banda media o una fuerte tinción de negro. Las orejas y el anillo orbital varían de blanco pardo a anteado. La cola, en el dorso es negra con un fuerte baño de blanco. Ventralmente, la cola es grisácea a café amarillento, con un borde de pelos negros y puntas blancas. Las partes ventrales del cuerpo varían de blanco con un baño de blanco amarillento pálido a un fuerte color ocre anteado. El pelaje en términos generales es denso y de cerdas burdas, el pelo del área del dorso medio mide alrededor de 15 mm de largo, el de la parte media de la cola es de 58 mm y cerca de la punta de la cola el pelo mide 80 mm. El pelaje interno es largo, y la cola es larga y esponjada. Tiene 4 glándulas mamarias: una pectoral, dos abdominales, y una inguinal.

Medidas externas

Las medidas externas promedio de S. oculatus son las siguientes: LT= 530-560mm.; LC=254-269mm; PT= 68-73mm.

Actual

MEXICO / DISTRITO FEDERAL

MEXICO / GUANAJUATO

MEXICO / HIDALGO

Registro marginal: Tulancingo; Real del Monte; Encarnación.

MEXICO / MORELOS

MEXICO / PUEBLA

Registro marginal: Monte Orizaba.

MEXICO / QUERETARO

Registro marginal: Pinal de Amoles.

MEXICO / SAN LUIS POTOSI

Los rangos de distribución de S. oculatus y S. alleni se acercan en San Luis Potosí, pero no son simpátricas, aún cuando no existen marcadas diferencias entre una especie y otra.

MEXICO / VERACRUZ

Registro marginal: Las Vigas; localidad tipo "cerca Las Vigas", Veracruz. Es una especie endémica del eje Neovolcánico transversal.

Original

MEXICO

Es una especie endémica al eje Neovolcánico. El género evolucionó en el Mioceno temprano, no se conocen fósiles de S. oculatus.

NOM-059-SEMARNAT-2001

Pr sujeta a protección especial

NOM-059-SEMARNAT-2010

Pr sujeta a protección especial

Su alimentación varía dependiendo del lugar en el que se encuentre, en San Luis Potosí, se ha reportado que se alimenta de bellotas e higos silvestres del género Ficus y piñas de varias especies de pinos.

El habitat preferido de S. oculatus es bosque de pino, encino y abeto en altitudes que varían de los 1500 a los 3600 msnm ya que se alimenta de semillas de estos árboles (Prunus).

Macroclima

En general el clima en donde se ha colectado S. oculatus varía entre climas frescos Cb por ejemplo en los bosques de oyameles, encinares altos, a semifríos como en los pinares Cwc.

Situación actual del hábitat con respecto a las necesidades de la especie

Ceballos y Navarro, (1991) reportan que el habitat ha sufrido severos daños causado por quemas, explotación de madera, y tumba del bosque para sembrar.

En Veracruz se observaron hembras en julio y agosto con mamas agrandadas, indicando la presencia de una camada temprana, pero no se observaron juveniles del año. Ausencia de hembras preñadas en julio y agosto. (Davis, 1944). .

La esguil de Peter (Sciurus oculatus) ye una especie de royedor de la familia Sciuridae.

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L'esquirol de Peters (Sciurus oculatus) és una espècie de rosegador de la família dels esciúrids. És endèmic de Mèxic, on viu a altituds d'entre 500 i 3.600 msnm. Surt poc quan fa fred. Els seus hàbitats naturals són les pinedes, les rouredes i les muntanyes àrides. Es creu que no hi ha cap amenaça significativa per a la supervivència d'aquesta espècie.

L'espècie fou anomenada en honor del naturalista alemany Wilhelm Peters.

Peters’ Hörnchen (Sciurus oculatus) ist eine Hörnchenart aus der Gattung der Eichhörnchen (Sciurus). Es ist in Zentral-Mexiko verbreitet.

Peters's squirrel (Sciurus oculatus) is a tree squirrel in the genus Sciurus endemic to Mexico. It was first described by the German naturalist and explorer Wilhelm Peters in 1863. Three subspecies are recognised. It is a common species, and the IUCN has rated its conservation status as being of "least concern".

La ardilla de Peter (Sciurus oculatus) es una especie de roedor de la familia Sciuridae.

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Sciurus oculatus Sciurus generoko animalia da. Karraskarien barruko Sciurinae azpifamilia eta Sciuridae familian sailkatuta dago.

Lo scoiattolo di Peters (Sciurus oculatus Peters, 1863) è una specie di scoiattolo arboricolo del genere Sciurus endemica del Messico.

Sciurus oculatus is een zoogdier uit de familie van de eekhoorns (Sciuridae). De wetenschappelijke naam van de soort werd voor het eerst geldig gepubliceerd door Peters in 1863.

Sciurus oculatus är en däggdjursart som beskrevs av Peters 1863. Sciurus oculatus ingår i släktet trädekorrar, och familjen ekorrar. IUCN kategoriserar arten globalt som livskraftig. Inga underarter finns listade i Catalogue of Life. Wilson & Reeder (2005) skiljer mellan tre underarter.

Denna ekorre når en absolut längd av 53 till 56 cm, inklusive en cirka 25 cm lång svans. Vikten ligger vid 640 g. Arten har grå päls på ovansidan och vit päls vid buken. Öronen är vita och på ryggens mitt finns ofta en svart strimma. Svansen har svart färg.

Sciurus oculatus förekommer i centrala Mexiko. Den lever i bergstrakter och på högplatå mellan 1500 och 3600 meter över havet. Habitatet utgörs av barr- och lövskogar. Arten besöker även torra klippiga delar av bergstrakter med lite växtlighet.

Sciurus oculatus äter nötter, mandel, frukter och andra växtdelar. Individerna är aktiva på dagen, främst på morgonen och på eftermiddagen. Allmänt antas att levnadssättet är lika som hos andra trädekorrar som lever i södra Nordamerika, till exempel grå ekorre (Sciurus carolinensis).

Поширення

Країни поширення: Мексика (Ґуанахуато, Ідальго, Мехіко, Пуебла, Керетаро, Сан-Луїс-Потосі, Веракрус). Зустрічається на висотах від 1500 до 3600 м. Цю вивірку можна знайти в соснових і дубових лісах і в посушливих горах.

Морфологія

Розрізнення. S. oculatus може бути симпатричним з Sciurus aureogaster and Sciurus deppei. S. oculatus (загальна довжина 530-560 мм) розміром приблизно з S. aureogaster (загальна довжина 418-573 мм), але S. oculatus має коренастіше тіло і не має P3. S. deppei (загальна довжина 343-387 мм), має P3 і є значно меншим, ніж S. oculatus. Зовні S. oculatus нагадує Sciurus carolinensis, особливо більш південні підвиди S. carolinensis. Найочевиднішою відмінністю є відсутність P3 S. oculatus. Генетичні відносини можуть бути ближчі до Sciurus niger, ніж до S. carolinensis.

Опис. Велика деревна вивірка. Верх або одноманітно сиво-сірий або є серединна смуга чи наповнення чорного кольору. Вуха і орбітальні кільця від тьмяно-білого до жовто-коричневого кольору. Зверху хвіст чорний з важким заповненням білого. Знизу від сиво-сірого до жовтувато-коричневого кольору з кордону чорного волосся з білими кінчиками. Низ варіює від білого кольору до блідо-жовтуватого збагаченого вохрово-буруватим. Смуги навколо очей добре помітні, у різних підвидів вони різного кольору. Хутро густе і грубе. Волосся по центру спини довжиною 15 мм, по центру хвоста 58 мм і на кінці хвоста 80 мм. Підшерстя довге. Є 4 пари молочних залоз. Зубна формула: I 1/1, C 0/0, P 1/1, M 3/3 = 20.

Поведінка

Було відзначено, що споживає мигдаль (Prunus), жолуді і дикий інжир (Ficus). Її період розмноження припадає на липень і серпень.

Загрози та охорона

Серйозних загроз для виду нема. Цей вид зустрічається в кількох природоохоронних територіях по всьому ареалу.

Посилання

• Álvarez-Castañeda, S.T., Castro-Arellano, I., Lacher, T. & Vázquez, E. 2008. Sciurus oculatus. In: IUCN 2011 (англ.)
• Troy L. Best Sciurus oculatus. Mammalian Species No. 478, pp. 1-3 (1995) (англ.)

Sóc Peters, tên khoa học Sciurus oculatus, là một loài động vật có vú trong họ Sóc, bộ Gặm nhấm. Loài này được Peters mô tả năm 1863. Chúng là loài đặc hữu của México.

페테르스청서(학명 : Sciurus oculatus)는 다람쥐과 청서속에 속하는 설치류의 일종이다. 멕시코의 토착종이다. 1863년 독일 박물학자 겸 탐험가 페테르스(Wilhelm Peters)가 처음 기술했다. 3종의 아종이 알려져 있다. 흔하게 발견되는 종으로 국제 자연 보전 연맹(IUCN)이 보전 등급을 "관심대상종"으로 분류하고 있다,