Trying to Repopulate

By: Ashley Gray and Martha Barajas

The New Species

A new species of squirrel was found on St. Kitt Island, in the Caribbean. Prior to finding this species any squirrel on the island and the adjacent island, Nevis, were thought to be Gray Cheeked Flying Squirrels. The new species, which is only on St. Kitt Island has been named Bartel’s Flying Squirrel.


In October of 1997, Josh Williams and a team from the Mammalian Research Center at Oregon State University were contacted by the Department of Nature and Island Resources of the West Indies to investigate the decreasing population of the Gray Cheeked Flying Squirrel on St. Kitt Island. The team determined that the present population of St. Kitt Island was 683 individuals, while Nevis population was 3582.

Initial Experiments

The team assumed these two species of Flying Squirrels where the same species. Josh’s team conducted 50 attempts to breed the St. Kitt squirrels and the Nevis Island squirrels. Unfortunately all attempts failed with no intercourse taking place between the two. Josh’s team then suspected that genotype variations were the cause of the failures. The team went on and conducted in-depth research to find the differences between the two squirrels. The team chose to test for carriers of a gene mutation from squirrel to squirrel, this test would hopefully show if there was a difference between the genes of each squirrel and if there was, what the difference was.

Reproductive Variations between species of flying squirrels.

Discoveries were made when studying the gray cheeked squirrel found in Nevis Island, and the bartel’s flying squirrel found in St. Kitt Island. The average time spent in courtship display of the gray cheeked squirrel was 21.3 seconds, and the time spent by the bartel’s flying squirrel was 12.6 seconds. This is one of the main reasons why the species were not able to reproduce. Also the gestation time of the gray cheeked squirrel is 42.7 days, and on the other hand the gestation time of the bartel’s flying squirrel is 29.3 days. This gives us a clue of why the reproductive process was not achieved, because the gestation necessities of specie vary greatly with the other.

Morphological Variations between species of flying squirrels.

Both squirrels’ looks are very similar, but researches have found other physical differences. First and most important was the hind limb. The gray cheeked squirrel’s average hind limb was 4.2 centimeters long, and the bartel’s hind limb was 4.2 cenemiters. There are other variations such as, weight, lenght, and forelimb sizes. This suggests the separations of the species for a long period of time, because they have evolved, and adapted to different environments which changed many of their physical characteristics.

History and Evolution

Previews research suggested that the islands were once together, which meant the species of flying squirrels were once able to reproduce. Now they are two miles apart, which created a geological isolation between species. This lead to allopatric speciation.  The gray cheeked flying squires phenotype of the hind lim is 4.2 centimeters, this evolutional difference was created due to the food supplies. Nevis island provides squirrels with low to the ground food, which means they don’t have to jump as high as the barrel’s flying squirrel for which the hind lim average size was 7.8 centimeters.

Recovery Plan

Even though our experiments have not been successful. We will try different methods to repopulate the bartel’s flying squirrel in St.Kitt Island. The next step we will try to take, is for the barrel’s flying squirrel to adapt to the environment of the gray cheeked squirrels so the courtship display changes. We are hoping this will help both species reproduce, besides the physical variations

Comment Stream