introduction: the persian squirrel (sciurus anomalus) is the only member of the sciuridae family found in the middle east. some people maintain them as pets, thus their referrals to veterinary hospitals has been increased recently. several morphological studies have been carried out mainly on the arch of aorta and its branches in common rodents, small mammals, and domestic animals but there are...

Much controversy exists regarding the species of the squirrel monkey. Napier and Napier (Whitney 1995) divide the squirrel monkeys into two species: Saimiri sciureus and Saimiri osterdii; the former is used in biomedical research. Hershkovitz prefers to use two groups of Saimiri based on facial characteristics and other factors, which include "Roman" and "Gothic" types. He suggests four species...

This experiment compared California ground squirrel (Spermophilus beecheyi) activity on replicated grazed and ungrazed pastures in a blue oak (Quercus douglasii) savanna. During the 4-year study, squirrel activity, measured as the number of active burrows, generally declined in grazed and ungrazed pastures without oak canopy. Squirrel activity declined least in grazed pastures with blue oak can...

Ouabain-sensitive K influx into ground squirrel and guinea pig red cells was measured at 5 and 37 degrees C as a function of external K and internal Na. In both species the external K affinity increases on cooling, being three- and fivefold higher in guinea pig and ground squirrel, respectively, at 5 than at 37 degrees C. Internal Na affinity also increased on cooling, by about the same extent....

Secretogranin II (SgII) is a member of the granin family of proteins found in neuroendocrine and endocrine cells. The expression and storage of SgII in the pituitary gland of Old World primates and rodents have been linked with those of luteinizing hormone (LH). However, New World primates including squirrel monkeys do not express LH in the pituitary gland, but rather CG is expressed. If CG tak...

Pituitary gonadotropins LH and FSH play central roles in reproductive function. In Old World primates, LH stimulates ovulation in females and testosterone production in males. Recent studies have found that squirrel monkeys and other New World primates lack expression of LH in the pituitary. Instead, chorionic gonadotropin (CG), which is normally only expressed in the placenta of Old World prim...

The squirrel monkey is the only primate reported to lack ocular dominance columns. Nothing anomalous about the visual capacity of squirrel monkeys has been found to explain their missing columns, leading to the suggestion that ocular dominance columns might be "an epiphenomenon, not serving any purpose" (Livingstone et al., 1995). Puzzled by the apparent lack of ocular dominance columns in squi...

Central American squirrel monkeys Saimiri oerstedii are limited to Costa Rica and Panama, and have never been abundant. The Costa Rican population is now decimated. Based on our survey of squirrel monkeys throughout a large portion of the Costa Rican range of this species in 1996, we can confirm that at least 1246 squirrel monkeys remain in 26 spatially dispersed localities. Despite probable un...

Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy, or prion disease, that affects deer, elk, and moose. Human susceptibility to CWD remains unproven despite likely exposure to CWD-infected cervids. We used 2 nonhuman primate species, cynomolgus macaques and squirrel monkeys, as human models for CWD susceptibility. CWD was inoculated into these 2 species by intracerebral...

The susceptibility of rhesus monkeys to motion sickness was investigated using test conditions that are provocative for eliciting motion sickness in squirrel monkeys. Ten male rhesus monkeys and ten male Bolivian squirrel monkeys were rotated in the vertical axis at 150 degrees/s for a maximum duration of 45 min. Each animal was tested in two conditions, continuous rotation and intermittent rot...