Does contraceptive rods affect the behaviour of African lions (Panthera leo leo) in captivity?

Navn: Anne Lucia N. Jansen,  Aarhus Universitet

The last couple of years there have been a great debate on how to solve the problem with surplus animals in the zoos and wildlife parks. Some uses the “Breed and Cull”-method where an animal gets to produce, but the offspring that there is no room or takers for, will be euthanized when they reach a certain age. Others sterilize their animals or inject them with contraceptive rods. The rods most frequently used are hormonal contraceptives. The rods work by preventing the eggs, in females, and sperm cells, in males, from maturation and thereby preventing offspring. Hormones are shown to affect both behaviour and morphology, but what about the rods? My study is an observational study and it was made in 8 different zoos in Denmark, Germany, Belgium and Netherlands. The aim of the study was to see if the contraceptive rods have an effect on the behaviour of female African lionesses in captivity. The results showed no significant difference between the two treatments (with and without rods), but this can be due to a small sample size. From this study it cannot be concluded whether or not contraceptive rods has an effect or not on the behaviour. Further studies should increase the sample size and include physiological measurements for getting a more reliable result.