An ethogram is an entire lexicon of the behavior of a species. Ethograms are important in studying animal behavior because, they provide a foundation for the observation of behavior. An ethogram is constructed by observing and recording all of the activities that an animals performs. In order to correctly record these behaviors, methods of sampling the behaviors must be used. There are various sampling methods used in performing observational studies of behavior. Previously you have observed a group of animals without the knowledge of any of these methods. In today's lab you will learn about several types of behavioral sampling methods, and then use them in observing the same group of animals you observed last week.
There are two types of behavior patterns that are often seen in animals that are at opposite ends of a continuum of behavior. The first type of pattern is called an event.
Events are behavior patterns of relatively short duration, such as discrete body movements or vocalizations, which can be approximated as points in time. The salient feature of events is their frequency of occurrence. For example, the number of times a dog barks in 1 minute would be a measure of the frequency of a behavioral event (Martin and Bateson 1995).The second type of behavioral pattern is called a state.
States are behavior patterns of relatively long duration, such as prolonged activities, body postures or proximity measures. The salient feature of states is their duration (mean or total duration, or the proportion of time spent performing the activity). For example, the total time a dog spends asleep over a 24-h period would be a measure of the total duration of a state (Martin and Bateson 1995).Behavioral Sampling Methods
In this sampling method, all of the actions of one animal are recorded
for a specified time period. For example, Animal A is being observed for
five minutes. During this five minute period, all of the activities that
this animal performs are recorded, while the activities of the other animals
in the group are not recorded. When the time period is up, the observer
moves on to Animal B to record that animal's activities. This continues
until all of the animals in the group have been observed for the specified
The instantaneous sampling method is a frequently used sampling method
in animal behavior. While using the instantaneous sampling method, the
observer records the behavior of an individual in a group at predetermined
time intervals. This sampling methods records states, rather than events.
An example of this sampling method would be to record the behavior of an
individual animal at one minute intervals for a twelve hour period of time.
Continuous sampling method is another sampling method that is frequently
used to observe behavior. When using this method, the observer simply records
all of the activity that occurs while the animals are being watched. This
sampling method is very helpful in recording social interaction between
two or more animals in a group. An example of this sampling method would
be to record when bunts, chases, fights, feeding bouts, nursing bouts,
etc., occur during the period of observation.
Scan sampling is very similar to instantaneous sampling. In scan sampling
the behavior of all the individuals in a group of animals are recorded
at predetermined time intervals. As with instantaneous sampling, states
are recorded instead of events. An example of scan sampling would be to
observe a group of animals and record the behavior of each animal in the
group at one minute intervals for a twelve hour time period.
Sampling Occurrences of a Specific Behavior
Sometimes during the course of observing animal behavior, certain behaviors
are performed by several of the animals at the same time. Usually one animal
starts a behavior, and then the other animals begin to perform the behavior.
This is called social facilitation. When this happens, the behavior can
be recorded as one event. This would be considered sampling a specific
behavior. For example, if all of the animals in the group being observed
are grazing, then this type of sampling can be used to record the behavior.
In this sampling method, the observational focus is on an interaction (behavior) instead of on an individual animals or group of animals. Sampling periods begin and end when a behavioral sequence begins and ends. For instance, if the observer is studying agonistic behavior (the aggressive and submissive behaviors displayed in a social context), the sequence of events that leads to an agonistic encounter between two animals (threat bunt chase) would mark the beginning of the sampling period. When the behavioral sequence has ended or is interrupted, then the sampling period ends.
This is only an abbreviated list of the types of sampling methods that exist for observing animal behavior. Many of these sampling methods may be used exclusively, or in conjunction with one another. The choice of which sampling methods is used depends on several variables such as: what behavior is being studied; which individuals are being studied; when are the studies taking place; where the studies are taking place; and the type of environment the studies are being conducted under. These variables must be considered carefully so that the data can be collected in the best possible way.
Altmann, J., 1974. Observational study of behavior: sampling methods. Behaviour 49:227-267.
Lehner, P.N., 1992. Sampling methods in behavior research. Poultry Science. 71:643-649.
Martin, P. and Bateson, P. 1995. Measuring Behaviour: An introductory guide. Cambridge University Press.
Observe the same group of animals that you observed last week for a one half hour period of time, using one or more of the sampling methods discussed. For example, 15 minutes of focal animal sampling and 15 minutes of scan sampling. Please remember: 1) Do not get in the pen with the animals being observed; 2) Do not feed the animals being observed; and 3) Do not disturb the animals being observed in any way. Compare the data collected from these observations to the data from the previous observation. In a one to two typewritten page paper discuss the differences between these data sets. Also discuss why you chose the sampling method(s) that you used. Finally, explain some of the merits of using a defined sampling method for observing behavior. Turn in your typewritten report, as well as your data from both observations a week from today. Be sure to include the species of animal you observed.
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