Milwaukee Public Museum

Britta Nordberg

What Made Me Want to Study Biology: The natural world has always fascinated me, so the decision to major in Biology came easily. In particular, I am interested in studying the interaction between animals and their environment.

Kinkajou

Though still relatively common within its native habitat, the kinkajou was added to the list of threatened species in 1996. The population of this mammal is declining due to both fur trapping and deforestation, the latter resulting in the general habitat loss affecting many carnivore species today.

We will investigate the relationship between cacao farming and a local kinkajou population, by conducting a study of four kinkajous whose home ranges include Julio Hernandez' cacao farm in the Upala region of Costa Rica. This region was chosen due to the high frequency of kinkajou sightings and for the rather unique reports of damage done to cacao plants by the kinkajous.

I hope to show the relationship between human constructions, particularly cacao farming, and kinkajou habitat. We hypothesize that kinkajous will spend more time in areas with a higher density of preferred plant resources.

Baiting and trapping a kinkajou on a farm bursting with ripe bananas is no small feat! Due to the impossibility of catching kinkajous, my summer's focus is going to be changed from kinkajous to sloths. University of Wisconsin-Madison professor Christopher Vaughan and field biologist Geovanny Herrera had previously established an investigation involving bloodwork on both two-toed sloths (Choloepus) and three-toed sloths (Bradipus). Nine of these animals have been fitted with radio collars and researchers are tracking the animals to learn more about their movement, habitat preference, diet and interaction with one another. Basically I will study in sloths what I meant to study in kinkajous.

We are using a radio frequency receiver and antennae to track the animals, often relying on collaborative triangulation with a field assistant to locate the sloths more efficiently. Some variables measured or recorded include the following: sloth name and date, GPS point, time of day, habitat type, behavior of the animal, position of the animal, animal's height in tree, species of tree, whether or not the animal changed trees, if the animal was easily visible from the ground, weather type and more. We also note whether the animal is resting, awake, moving, eating or self-scratching. I recorded animal position as either hanging, sitting, lying on back, on the ground, or standing erect on its hind limbs only.

Without having analyzed the considerable collection of GPS points I recorded over the summer, I can only comment on the general trends of the data.

In general, both male and female three-toed sloths changed trees equally no matter what time of day, about 50% during the day and 50% overnight.

Two-toed sloth females, on the other hand, were much more likely to change trees between overnight than they were during the day; these sloths made nearly 73% of their displacements overnight, while daytime displacements accounted for only 23% of their tree-to-tree movement. This data seems to show that three-toed sloths appear to move from tree to tree during the day, while two-toed sloths usually move in the evening or overnight.

Though I have returned to the United States, data will continue to be collected through the month of August by a field assistant. After this period of time, I plan to re-analyze the data set in full and hope to begin analysis of the GPS data as well.