Questions: Animal Behavior: Proximate and Ultimate Causes

Question 1

A biologist says that male birds sing in spring because rising day length raises their testosterone levels. What kind of explanation is this?

• A. Ultimate, because it involves evolution
• B. Proximate, because it describes the physiological mechanism
• C. Neither, because hormones do not affect behavior
• D. Ultimate, because it involves the seasons

Answer: (B)

Day length and hormones describe how the behavior is triggered and controlled, which is a proximate explanation. An ultimate explanation would be that singing attracts mates and defends territory, which increases reproductive success.

Question 2

Imprinting in geese can occur at any age if the young bird is shown a suitable object.

• T. True
• F. False

Answer: False

Konrad Lorenz showed that greylag goslings learn to follow the first moving object they see during a short sensitive period after hatching. After that period ends, imprinting on a new object is much harder or does not occur.

Question 3

Tinbergen found that male three-spined sticklebacks attack crude models with a red underside but ignore realistic models without red. What does this show?

Model answer: The attack is a fixed action pattern triggered by a sign stimulus, the red belly that rival males display in the breeding season. The male responds to that simple cue, not to the whole appearance of another fish.

Sign stimuli let animals respond quickly to key features of their surroundings. The same reliance on a simple cue also makes the response easy to trigger with unrealistic objects.

Question 4

A sea anemone stops retracting when a researcher touches it gently over and over without harm. This simple form of learning is called:

• A. Imprinting
• B. Habituation
• C. Operant conditioning
• D. Spatial learning

Answer: (B)

Habituation is a decrease in response to a repeated stimulus that carries no information or consequence. It saves energy and attention for stimuli that matter.