Elephants Elephants - Wildpro - Twycross Zoo

3.7.2 African Elephant
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NORTH AMERICA
The population is declining, the reasons for this include; lack of reproduction,
poor calf rearing, a perceived shortened reproductive and total lifespan in
captivity, small percentage of males who are proven breeders and an aging
population [Olson & Weise 2000 #1840]. Only 25 calves had been born as of
1.1.1999 (the first one in 1978) and of these only six remained alive by the end
of 1999 (although two calves were born in 2000 as a result of AI). Recently
(Wiese and Willis 2004) it has been shown that the African elephant average
life expectancy in North America is 33 years.
A similar picture to that already discussed for Asiatic animals exists in that
33% of calves died within the first month of birth. However the population is
relatively young and has the potential to become self-sustaining if
reproduction and juvenile survivorship increase; as of 1.1.1999 there were 246
(35.211) living in North America and by October 2001 was 236(34.202) with 3
born in the preceding year and four pregnant animals. Predictions suggested
that immediate action is required to achieve pregnancy in as many cycling
females as possible.
EUROPE
All information on the European programme was provided by Amelia Terkel,
Ramat Gan, the EEP coordinator and studbook keeper. In October 2005 there
were 203 living animals (48.155), the oldest being a female aged 55. Since 1980
64 have been born in European collections, of which 57 survived for more than
one year, a survival rate of 89%. This is exceptionally good, and much better
than the North American region for both species and Europe for Asians. The
population is relatively young, with the bulk of females aged under 40 and
males under 30. The number of young born each year is increasing (see graph,
Fig. 10). However the population is not yet self-sustaining (Hulbert 2004): in
order for this to occur fecundity would need to be considerably increased.
The main problem is that there are not sufficient females in breeding
situations There are currently 38 founders with living descendents (of which
23 are alive), but there is potential for the number of founder to increase
significantly. The breeding population is 48 (12.36) with a further animals
currently pregnant, there is thus excellent potential for this population to
become sustaining. However it should be noted that currently there is not a
sufficient genetic base for either population to retain 90% of genetic diversity
for 100 years.
The studbook keeper anticipates that within the next five years, 20.51 animals
in 24 locations should constitute the breeding population which may prove
sufficient for a self sustaining population.