Female Mate Choice and Reproductive Management of Koalas
Very little is known about the reproductive biology and behavior of koalas.
Play the male koala bellow below. If your browser does not support the embedded player, click here.
Despite their enormous popularity in zoological institutions, very little is known about the reproductive biology and behavior of koalas Phascolarctos cinereus. Jennifer Toby and Dr. Fred Bercovitch of the Behavioral Biology Division of the San Diego Zoo's CRES are trying to unravel the mysteries of mate choice in koalas. The focus of this project is to try to identify how male auditory and olfactory communication influence breeding sucess.
Koalas have an extensive repertoire of vocal signals, and one particular vocalizaiton, the bellow, has featured prominently in discussions of koala behavioral biology. Male bellows attain their crescendo during the mating season. The bellows could provide a remote advertisement governing female attraction or male repulsion in the wild.
The koala acoustic communication study at the San Diego Zoo has been designed to determine the specific attributes of vocalizations that influence male breeding success. Sophisticated recording equipment and software dissect vocal communication into multiple components, the most important being the fundamental frequency and formants of calls.
To date, 80 bellows from 11 males have been recorded. Male bellows range in duration from 15 seconds to 2.5 minutes. The time spent bellowing seems to be inversely related to age, with younger males (3.5 to 4 years old) producing longer bellows than older males. Sometimes bellowing by one male will stimulate others to sound off, resulting in a chorus of bellows.
Male koalas have sternal scent glands used for marking trees and other surfaces. As with bellows, scent marking seems to attain a zenith during the breeding season and might also function in the context of mate attraction or repulsion of male competitors. Male bellows may be acoustic signals and scent marking is an olfactory signal, functioning as proximate mechanisms mediating sexual selection. Preliminary analysis suggests that each male emits an individually specific scent.
Understanding the vairous communication systems of koalas can lead to more efficient breeding protocols in captivity and can provide a more solid foundation for conservation management plans in the wild.
