The BBC’s Winterwatch program recently featured Dr. Sean Twiss, who has spent the last 30 years researching the behavior of seals. Here, Dr. Twiss of the Department of Biosciences expands on his most recent findings and explains why seals are as unique as people.
Describe your research on the behavior of seals.
My research examines individual variations in seal behavior to advance our understanding of why some seals are more successful than others. Our previous research has shown that seals exhibit distinctive behavioral patterns, and our current study uses heart rate monitoring to examine the physiological correlates of these behavioral variations.
For the past five years, our study has monitored a colony of seals on the Isle of May, off the east coast of Scotland, during the mating season. Our research has focused on seal mothers who raise their pups on shore.
We used specially designed heart rate monitors to obtain information about heart rate patterns and fluctuations while the seals were relaxed and under stress. Stressors were both man-made and natural, such as unwanted closeness or attention from other seals. To test how different seals responded to the same stress trigger, we used a remote-controlled car to drive close to the seals and deliver a minor auditory stressor (a wolf cry).
Throughout our five-year study, we have observed that different seals regularly behave and respond in various ways, displaying characteristics such as self-confidence, shyness and reactivity, related to individual variations in their physiological reactions.
This runs counter to conventional thinking, which holds that natural selection should drive all people toward a single ideal way to solve the problems in the natural world we are studying. The seals show several answers to their problems instead of just one.
In addition, we have discovered that the behavioral reactions of the seals to stressful situations do not always coincide with those of their bodies. We found that a seal’s heart rate can remain for a considerable time after a stressful incident, although it can quickly return to a resting behavioral state. Because seals must conserve energy, especially during mating season when they must produce high-fat milk for their pups, a higher heart rate still uses additional energy. Assessing the effects of animal-human interactions such as ecotourism could greatly benefit from understanding these physiological and behavioral responses to stress.
Finally, we found that the physiological reactions of seals to anthropogenic (human-caused) disturbances were comparable to those of animals to natural disturbances. Many people worry about how humans disrupt breeding colonies, but our research reminds us that life is stressful for all animals, even seals. Natural selection examines how people handle the daily pressures of living and procreating. Therefore, the question is not whether each seal can withstand stress, but rather whether such capabilities can withstand the additional stress that human activities may bring.
This research project is coming to an end. However, I would like to explore the possibilities of observing some of the seals individually when they are at sea to see how we can reflect their physiology and behavioral traits in their foraging strategies. For example, consider whether braver people go further to get food.
I am particularly interested in applying parts of the research methodology to sheep populations in the North East of England to learn more about how sheep individuality influences grazing patterns.