The Central American Dwarf Squirrel is also known as Alfaro's Pygmy Squirrel. Evidence suggests that this genus is polyphyletic. The entire radiation of tree squirrels in South America appears to have descended from a single lineage that entered the continent with the establishment of the Panamanian isthmus. The divergence between tree squirrels of Central and those of South America closely corresponds in time to the formation of this land bridge. Before then, there was no evidence of squirrels in South America.
Because Central American dwarf squirrels tend to stay hidden in heavily forested areas, there is currently no information about their forms of communication and perception.
Communication Channels: visual ; acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
Central American dwarf squirrels occur in Monteverde National Park, Talamanca National Park, and other protected areas.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
No negative feedback has been reported.
The economic importance of these squirrels has not been evaluated. However, as with all squirrels that have a diet consisting of nuts and seeds, they may act as seed dispersers.
Ectoparasites, such as mites and chiggers, use this species as a host.
Ecosystem Impact: disperses seeds
Commensal/Parasitic Species:
The only Microsciurus alfari stomach contents that have been examined contained material too finely divided to identify. However, it is likely that they eat nuts from the ivory-nut palm groves that they inhabit. They probably have a common granivore diet consisting of seeds, grains, and nuts.
Animal Foods: insects
Plant Foods: wood, bark, or stems; seeds, grains, and nuts; fruit
Foraging Behavior: stores or caches food
Primary Diet: herbivore (Granivore )
Central American dwarf squirrels, also known as Alfaro's pygmy squirrels (Microsciurus alfari), are native to Colombia, Costa Rica, Nicaragua, and Panama. However, abundance in Nicaragua may be limited, to date; only one specimen has been found there, in 1917.
Biogeographic Regions: neotropical (Native )
Dwarf squirrels (Microsciurus) are found in tropical rainforest regions of Central and South America. None of the members of this genus are endangered, although they are rarely seen because they are shy and lead hidden lives.
Dwarf squirrels show a decided preference for heavy forest, particularly those with vines in the undergrowth. In such places, they can descend to the ground and escape by running across the forest floor or find the nearest tree and climb out of sight. Their small size, dull coloring, and quickness make them difficult to catch. Although they are not abundant, the population numbers within this genus may exceed those of larger squirrels.
Range elevation: 1500 ft. to 5300 ft. km.
Average elevation: 3000-4000 ft. km.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: forest ; rainforest
There is currently no available information about the lifespan of this species.
Dwarf squirrels are not as small as their name may suggest. They have a head and body length of 15 centimeters (5.9 in) and a long tail, measuring approximately 12 centimeters (4.7 in). These measurements are similar to those of red and gray squirrels. The majority of their body is dark olivaceous brown. However, their head has a reddish-brown hue. They are fulvous grey below their head and on the underside of their limbs; however, the color can vary from a buff, fulvous grey or a rufous hue. Their skull is highly arched, with pronounced swelling on the frontals at the plane of the postorbital processes. Their brain case is strongly deflected at the posterior end and the rostrum is short and broad. Their upper incisors project forward to, or beyond, the plane of the tip of the nasals, and their jugal is relatively wide. Their inferior margin is abruptly depressed anteriorly where it joins the maxilla.
Average length: 27 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry ; polymorphic
Small rodents are frequently on the menu for carnivores and birds of prey. Even though there are no specific reports of predation on this species, it is reasonable to assume that they are preyed upon by other animals.
An anti-predator adaptation that Central American dwarf squirrels possess is their small size and dull coloring; this allows them to blend into heavy forest coverings.
Anti-predator Adaptations: cryptic
There are no data on the mating system of this animal.
Although data are lacking on the reproduction of this species, it is reasonable to assume that their young, like most squirrels, are altricial. It is also probable that their breeding season is likely in April, May, and June, as in other squirrels. This notion was further supported by the collection of a male specimen whose testes were in breeding condition during the month of June.
Breeding season: Central American dwarf squirrels likely mate during the months of April, May, and June.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization ; viviparous
As in all mammals, the female provides parental care by nourishing her young with milk. It is likely that, as in other squirrels, the young are born in a nest of some sort, with their eyes closed. The mother likely cares for the young in the nest until they are able to venture forth on their own.
Parental Investment: altricial ; female parental care
The Central American dwarf squirrel, also known as Alfaro's pygmy squirrel,(Microsciurus alfari) is a small tree squirrel in the genus Microsciurus and tribe Sciurini found in Colombia, Costa Rica, Nicaragua, and Panama. No species of squirrel within this genus are endangered, but they are rarely seen because they are shy and live hidden lives. This suggests that their population numbers may be larger than documented.[2]
Central American dwarf squirrels are not as small as their name suggests. In fact, their body measurements are close to that of the Red Squirrel and Gray Squirrel, with a head-and-body length about 15 cm (5.9 in) with a 12 cm (4.7 in) long tail. The majority of their body is a dark, olive-green and brown color with a reddish-brown head coloration. The underside of their heads and limbs can range from a yellowish grey to a tawny grey color.[2]
Central American dwarf squirrels are native to Colombia, Costa Rica, Nicaragua, and Panama. They typically inhabit tropical rainforests, with a preference for the heavy forest, particularly those with vines in the undergrowth, which can allow them to descend to the ground and quickly escape from predators. [3]
Central American dwarf squirrels are typically very shy and solitary in nature. While they are diurnal some squirrels have been observed at night by hunters, suggesting a degree of nocturnal activity. Their small size, dull coloration, and quickness tend to make them hard to locate and catch or even observe.[2] The diet of these squirrels is most likely similar that to the common herbivore, consisting of seeds, grains and nuts, including nuts of the ivory-nut palm tree which they inhabit.[3]
The table below lists the six recognized subspecies of Microsciurus alfari, along with any synonyms associated with each subspecies:[4]
Microsciurus alfari taxonomy Subspecies Authority Synonyms M. a. alfari J. A. Allen (1895) none M. a. alticola Goodwin (1943) none M. a. browni Bangs (1902) none M. a. fusculus Thomas (1910) none M. a. septentrionalis Anthony (1920) none M. a. venustulus Goldman (1912) noneThe Central American dwarf squirrel, also known as Alfaro's pygmy squirrel,(Microsciurus alfari) is a small tree squirrel in the genus Microsciurus and tribe Sciurini found in Colombia, Costa Rica, Nicaragua, and Panama. No species of squirrel within this genus are endangered, but they are rarely seen because they are shy and live hidden lives. This suggests that their population numbers may be larger than documented.
