Ethogram & Behavior Essay
ETHOGRAM AND BEHAVIOR SAMPLE
For this assignment, I observed a gray squirrel. Squirrels are interesting animals to observe and study. Apart from having a rich and complex range of behaviors, squirrels are easy to observe. Squirrels are indigenous to Africa, the Americas, Europe and Asia. In general, squirrels range in size from 7-10 cm in length, and 10 g in weight, to 53–73 cm in length, and 5-8 kg in weight. They characteristically have lean bodies with shaggy tails and big eyes. Squirrels can be found in nearly every habitat from tropical rainforests to semi-arid deserts, only keeping away from high Polar regions and very dry deserts. Most gray squirrels live in tree hollows while others construct nests with twigs and plant material. They are primarily herbivorous, feeding on seeds and nuts, but some feed on insects and small vertebrates. The observations of this ethogram were done in the campus arboretum on the gray squirrels.
The campus arboretum is a quite place with lots of oak trees and lawns. It is also bordered by a forest reserve area. A group of gray squirrels within close proximity of each other was observed for this assignment on the 24th of April 2011 from 2pm to 4pm. During the day, a sizeable number of people are usually present at the arboretum but most of them go to relax and hence do not cause any disturbance to the animals in the arboretum. Many species of birds are also present in this location and have built their nests on the numerous trees. The huge trees in this location provide shade hence the arboretum is mostly cool even when the climatic temperature is high.
The observations were done from a bench at the arboretum. As I observed the squirrels, I stayed close enough to see all their activities but not too close to disturb them by my proximity. Four to six individual gray squirrels were observed for two hours and notes on their different activities were taken.
The squirrels were observed as being in an “alert” position most of the time. Two types of “alert” positions were observed. For the first type, the squirrel raised itself up on its posterior legs, held its paws up, sniffed the air, and then scanned its surrounding once or twice. The squirrels adopted this stance from time to time and held it until they finished. For the second type of “alert” position, the squirrel stopped in mid-motion, and stood completely motionless, with its ears perked up. The squirrel maintained this position for some time without raising itself up.
Occasionally, the gray squirrel broke into a run starting with an impulsive dash in one direction, often different from the direction it was facing initially. The squirrel ran with its limbs gripping surfaces for support. The run would go on for two to five minutes and did not always end at a particular target object.
The squirrels were very skilled at jumping and climbing on trees. To jump on a tree, the squirrel would start off by running then push itself off the ground using its hind legs. The squirrel would land somewhere around 30 to 50 cm above the ground. It would then climb and clamber up a tree, one paw after the other, moving swiftly without hesitation. When the gray squirrel stopped at a branch, it began to move horizontally towards the top of the branch.
The squirrels were also observed to meander around. They moved around at a much more leisurely pace when there were no people walking nearby. Their meandering actions involved the squirrels walking to one area, and then using the first alert behavior.
The squirrels were observed to feed on nuts, seeds, and wild fruits, some of which grew on the trees in the arboretum and others that had fallen off the trees. They picked items using both forearms, placing each paw firmly on either side of the nut/fruit. The squirrel then brought the item closer to its nose and sniffed it before it attempted to bite it or discard it.
When they came across a heap of leaves or other natural garbage, the squirrels dug through the heap using rapid coordinated movements of their arms. Each arm was raised above the squirrel’s chest as it plowed downwards through the heap in a circular motion.
When disturbed and prior to aggressive interactions, the tail and body hair of squirrels become erect. It was also observed that the squirrels flicked their tails rapidly when alarmed. These behaviors were however observed far between. There was minimal interaction between the the squirrels as they fed and moved separately and often ignored each other.
The table below shows the frequency and total amount of time that the squirrels spent on the activities described above.
Total Time (Minutes)
Frequency and time spent by squirrels on different activities
Time on activity = Ta
Percentage time on activity = Ta/ Tt * 100
Percentage time on alert type 1 = 15/120 * 100 = 12.5%
Percentage time on alert type 2 = 10/120 * 100 = 8.33%
Percentage time on climbing = 20/120 * 100 = 16.67%
Percentage time on running = 15/120 * 100 = 12.5%
Percentage time on meandering = 20/120 * 100 = 16.67%
Percentage time on foraging = 30/120 * 100 = 25%
Percentage time on social activities = 10/120 * 100 = 8.33%
From these statistics, we see that the squirrels spent the largest part of their time (25%) foraging while alert type 2 and social activities took up the least amount of their time (8.33% each). Running was observed the highest number of times while social activities were observed the least number of times.
It is highly likely that the time spent on foraging was high because the observation was done during the day. Most squirrels are characteristically diurnal; active during day time and sleep at night. Gary squirrels are generally asocial as indicated by the limited time they spent engaging in social activities. There was no difficulty in observing and interpreting the behavior of the squirrel although they kept alternating quickly between activities.
Further studies should be carried out on the communication mechanisms of squirrels. Individuals in any social system must be able to communicate with each other. Most animals use signals to convey messages. During my observations I did not observe any communication between the squirrels. Research should be carried out to investigate this aspect.