November 24, 2009 § 2 Comments
We can’t escape it, Christmas is round the corner! And this week’s news includes an update on Santa’s favourite animals, as well as news of some more births at the zoo!
Reindeer are of course a favourite Christmas-time animal. How would Santa power his sleigh without them? Nevertheless, before the reindeer can get in training for their seasonal duties, they first have to go through the last of the changes linked to their annual rut.
By this time of year, the rut has ended, meaning that the males can now loose their redundant (and rather heavy) antlers. Antlers are required throughout the rut for attracting and impressing females, as well as fighting off challenging males. Over the rutting season, adult males may loose a lot of weight as they expend energy on rut activities, and have little time for feeding. This puts them in a pitiable position ahead of the bleak winter months. Carrying around the unnecessary weight of antlers would make things even harder! Adult males will therefore shed their antlers during November/ December, leaving them with just two pedicles (a permanent point or nub, protruding from the skull, and covered in skin). The shedding process takes two to three weeks to complete, and is pain free for the reindeer. Adult males can then focus their remaining energies on finding food.
Reindeer are the only deer species for which females also grow antlers. Females do not shed their antlers until after their calves have been born in spring/ summer. At this time of year, females have reached their maximum weight and are far better prepared for the long winter months. Their antlers are also much smaller than males, and therefore far less cumbersome. It may therefore be advantageous for females to remain armed with antlers during the winter months to assist them in self defence, whilst carrying young. The male reindeer will certainly have lost all interest in watching over the females by this time!
Young males will also retain their antlers until springtime as they do not yet have the hormonal cues which trigger the behavioural and physical changes linked to the rutting season. Why not pay our reindeer a visit, and take a look at the one adult male still resident at the zoo, ‘Eskimo’? He looks far less impressive after loosing his antlers, and may even have to endure being pushed about by the females and younger males a bit!
Spot the pedicles!
You may recall that our bird keepers worked very hard over the summer on breeding vulturine guineafowl. This involved artificially incubating the eggs and then hand rearing chicks in order to greatly increase the potential number of hatchlings within the breeding season.
A vulturine guineafowl pair will typically produce four to eight chicks within one season, if left to their own devices. This is because caring for eggs and rearing chicks exerts an energy demand on the parents, limiting the number of young they can successfully raise. However, if these parental responsibilities are taken on by the keepers instead, the guineafowl will continue to lay clutches of eggs, and can ultimately produce more young.
We are pleased to announce that a grand total of 23 chicks have now hatched and have been successfully raised by the keepers. Due to this large number, the youngsters are being kept off show before leaving for other zoological collections. Vulturine guineafowls are in demand in captivity, as their total captive population currently only amounts to around 300 individuals. These youngsters should therefore make a great contribution to captive collections. This success is also a tribute to the hard work and expertise of our bird keepers. We hope that they will be able to apply these reproductive techniques to other species in need of captive breeding efforts, in the future.
The very funky looking vulturine guineafowl!
We are pleased to announce that a warthog piglet was born on the 25th Sept. The youngster has been identified as a female, but has yet to be named. This birth is excellent news as it is the first since a new male, 2 year old ‘Otto’ arrived at the zoo to be paired with our 5 year old mum, ‘Blister’. Warthogs reach sexual maturity at around 24 months, and so Otto has certainly not wasted any time!
Blister’s youngster should be starting to graze now, but will not be weaned completely until around 4 months of age. Blister has proved to be a good mum, and can still be seen feeding her youngster, playing with it and protecting it from grumpy Otto! This is particularly important as male warthogs can be significantly larger than females, and do not usually live as part of the family group. They have no natural paternal instincts, and sometimes accidentally harm their own young!
Why not pay the warthogs a visit next time you are in the zoo? Unsurprisingly, you are more likely to see them out and about on sunny, warm days, rather than cold, wet days!
Blister acts the protective mum