Behavioral Endocrinology
Behavioral endocrinology is the study of how hormones and behavior interact. Hormones are chemical signals produced by your body, and they can have a strong influence over your behavior. Conversely, your behavior can also modify patterns of hormone expression.
Understanding the interaction between hormones and behavior is important, because it can have substantial consequences for an individual's Darwinian fitness (survival and reproduction).
Understanding the interaction between hormones and behavior is important, because it can have substantial consequences for an individual's Darwinian fitness (survival and reproduction).
How do we study behavior?
For this project, we employ three different methods for studying behavior.
For captive lynx, we rely primarily on keeper evaluations of an individual's behavior. Understanding an animal’s behavior means not only knowing what they do, but how they do it. People who interact with animals on a regular basis assimilate information about an individual’s temperament over time, and thus keeper surveys can be used to reliably assess an animal’s patterns of behavior, or "behavioral type."
We also conducted direct behavioral observations on a subset of the captive lynx in the study. This allowed us to 1) determine how these quantitative assessments of lynx behavior compare to the qualitative assessments provided by the keeper surveys, and 2) monitor responses to three different stimuli: a snowshoe hare distress cry, beaver castor scent, and a mirror (see photo). These behavioral tests allow us to assess how different individuals respond to different sensory stimuli.
For reintroduced and wild lynx, we need to take a whole different approach to studying behavior. Since the lynx cannot be observed directly, all information about their behavior comes from indirect observations. All reintroduced lynx and several naturally-occurring lynx are radio-collared, so information about their movement patterns can be obtained via satellite or airplane. Furthermore, in the winter months, biologists track lynx on foot to get more detailed information about lynx behavior. They follow an individual’s tracks through the snow, recording information about the habitat the lynx moves through, where it rests, how successful prey-chases are, what it kills, and with which other lynx it interacts.
For captive lynx, we rely primarily on keeper evaluations of an individual's behavior. Understanding an animal’s behavior means not only knowing what they do, but how they do it. People who interact with animals on a regular basis assimilate information about an individual’s temperament over time, and thus keeper surveys can be used to reliably assess an animal’s patterns of behavior, or "behavioral type."
We also conducted direct behavioral observations on a subset of the captive lynx in the study. This allowed us to 1) determine how these quantitative assessments of lynx behavior compare to the qualitative assessments provided by the keeper surveys, and 2) monitor responses to three different stimuli: a snowshoe hare distress cry, beaver castor scent, and a mirror (see photo). These behavioral tests allow us to assess how different individuals respond to different sensory stimuli.
For reintroduced and wild lynx, we need to take a whole different approach to studying behavior. Since the lynx cannot be observed directly, all information about their behavior comes from indirect observations. All reintroduced lynx and several naturally-occurring lynx are radio-collared, so information about their movement patterns can be obtained via satellite or airplane. Furthermore, in the winter months, biologists track lynx on foot to get more detailed information about lynx behavior. They follow an individual’s tracks through the snow, recording information about the habitat the lynx moves through, where it rests, how successful prey-chases are, what it kills, and with which other lynx it interacts.
How do we monitor hormone expression?
There are thousands of hormones that circulate through an animal’s body in the course of a day, helping to ensure that the body continues to function normally. Steroids are one class of hormones that play a critical role in physiological processes (just ask athletes how powerful these hormones can be!). This class includes several hormones that are important for reproduction (testosterone, estrogen, and progesterone) and also hormones that help the body respond to stress (glucocorticoids). While the body “recycles” most hormones, it disposes of steroid hormones in urine and feces. Fecal hormone monitoring is rapidly becoming a popular tool for monitoring an animal’s reproductive status or stress level, especially because it is non-invasive.
Steroid hormones pass through the liver and the gut before they are deposited in feces. Therefore, the hormones in feces are actually hormone metabolites, not pure hormones. Fecal hormone metabolites are extracted using a solution of ethanol and water (#1 on figure below). Then the fecal extract, which contains an unknown concentration of hormone metabolites (UH), is added to a micro-titer plate well which is coated with specific antibodies (e.g. testosterone antibodies; #2). A known amount of specially labeled hormone (LH) is also added to the well (#3). The UH from the extract and the LH undergo a competitive binding process with the antibody. The label on the LH causes a color change, and the intensity of the color indicates the amount of hormone metabolites in the feces (#4). If there are very few UH in the fecal extract, then a lot of the LH binds to the antibody and creates a darker color (#4 top). Conversely, if there are a lot of UH in the fecal extract, then only a few LH bind and the color is very light (#4 bottom).
Steroid hormones pass through the liver and the gut before they are deposited in feces. Therefore, the hormones in feces are actually hormone metabolites, not pure hormones. Fecal hormone metabolites are extracted using a solution of ethanol and water (#1 on figure below). Then the fecal extract, which contains an unknown concentration of hormone metabolites (UH), is added to a micro-titer plate well which is coated with specific antibodies (e.g. testosterone antibodies; #2). A known amount of specially labeled hormone (LH) is also added to the well (#3). The UH from the extract and the LH undergo a competitive binding process with the antibody. The label on the LH causes a color change, and the intensity of the color indicates the amount of hormone metabolites in the feces (#4). If there are very few UH in the fecal extract, then a lot of the LH binds to the antibody and creates a darker color (#4 top). Conversely, if there are a lot of UH in the fecal extract, then only a few LH bind and the color is very light (#4 bottom).
