Site Guide:

Mating System

Photo credited to Worldkids.net

As stated on the previous page, older African elephants remain sexually active. As a matter of fact, it is the older elephants that are often the most successful reproducers. This is the case because African elephants are a promiscuous species. The bulls do not help raise the young - the cows, with help from the kin group, accomplish this task. The bulls spend short periods of time courting the females. He may caress her with his trunk or place his trunk in her mouth, ear, or against her trunk. Males also use their trunk to check to see if a female is in estrus or not. If a female is in estrus, then a male may stay with her for several days to maximize his chance of reproduction. However, no bond is formed (Poole, 1989). Kinship groups work together to raise the young. Although the mother acts as the primary care giver, other members of the group help out quite a bit. In some rare instances, cows other than the calf's mother have been witnessed to allow the calf to suckle (Lee, 1987). This is extremely rare, however, and many researchers believe that it happens on accident when the cow is not paying attention.

Similar to the cycle of estrus in females, males experience periods of heightened sexual activity and aggression known as musth. During musth, testosterone concentrations are elevated. Musth bulls are extremely aggressive towards other bulls, and they tend to consequently increase in dominance for the period of time that they are in musth. When in musth, bulls secrete a thick substance from the temporal glands on the sides of their heads. This substance gives off a pungent aroma that serves to warn other bulls of the musth bulls current state. Young musth bulls give off a much less pungent aroma. The secretion from a young musth bull smells like honey, whereas an older musth bull tends to smell much less pleasant (Rasmussen et. al., 2002). In addition to the secretions from their temporal glands, musth bulls will also dribble urine. This alerts both other bulls and cows to the fact that the bull is in musth. Other bulls can avoid being attacked by a musth bull because they can find a urine trail and avoid the musth bull at the other end of it (Poole, 1989). Thus, all parties are content. The musth bull can search for a female without being interrupted, and the non-musth bull can avoid a dangerous battle. Musth bulls also produce a low-frequency 'musth rumble' that acts to attract females and alert males (DiSilvestro, 1991). Cows in estrus tend to prefer musth bulls to non-musth bulls. The state of musth also leads to fewer highly aggressive interactions between bulls. Interestingly, when two musth bulls encounter one another, the lower ranking musth male will often drop out of musth. If a lower ranking musth bull comes into contact with a higher ranking non-musth bull, the non-musth bull will recognize the musth bull as being dominant. (Slowtow et al., 2000). The period of musth, unlike estrus, is asynchronous. Being in musth for up to two months, bulls tend to lose a lot of weight. They spend this time searching for mates and eating less. Because of these energy expenditures it is advantageous for a bull to go into musth when the females are most receptive. This occurs during the rainy season. For this reason, researchers once thought that musth was actually some sort of male sex cycle when in fact the apparent cycling is actually due to an optimized cost-benefit scheme of mating (Poole, 1989).

Home
Predators
Habitat/General info.
Mating System
Social Spacing
Social Organization
Photo Gallery
Interesting Facts
References
Animal Behavior Home Page
Dr. Verna Case's Homepage
Davidson Homepage

The estrus cycle of the females can last up to about two and a half weeks and occurs once every month or so (Sikes, 1971). Adult bulls between the ages of 25 and 35 tend to only be successful at securing females who are early or late in their period of estrus. The bulls that are above the age of 35 are often the only bulls successful in securing mid-estrus females. Thus they reproduce the most. (Poole, 1989). The idea here is that the older a bull survives to become, the better his genes must be. Old males that remain healthy and high in the dominance hierarchy, thus, are the most desirable mates - due to the fact that their genes are partially responsible for their health, vigor, and strength/dominance. For this reason, females often avoid the advances of younger males and make low frequency calls to attract older, more dominant males with which they are willing mate. These older, more dominant males will also help to drive away the younger males and stop their advances on the female. These advances, which may come in the form of chasing, cost the female quite a bit of energy (Disilvestro, 1991). Thus it is doubly to the female's advantage to call for other males to both mate with a male whose genes are superior, and save time and energy by not being chased around by the younger male.

S. K. Sikes, public domain

The picture above shows how a mother assists her calf when it is attempting to take its first steps (Sikes, 1971).

Working cooperatively, the cows help to raise and defend each other's offspring (Sikes, 1971). This is understandable in terms of kin selection. The members of the kinship group are all related in some capacity, thus, helping raise the offspring of another cow serves to pass some of the individual's genes on and is thus worth the effort that it costs. This explains why kinship groups will herd between a predator and the calf/juvenile elephants when they are stressed by the presence of a predator.

Onward to the Social Organization!

 

This web site was created in partial fulfillment of the requirements for Biology 323, Animal Behavior, at Davidson College in the Spring Semester 2002.