With the peak of winter fast approaching, the mornings and evenings are starting to have a definite chill about them. Setting off from camp on mid-winter mornings, the standard procedure for most guests is to be layered up in all the warm clothes possible, wrapped in a cosy blanket with a hot water bottle on their lap. It would only be fitting to shed a bit of light on what a few of the different animals do to survive the colder period of the year.
Firstly, some animals such as some species of birds, are lucky enough to have the choice to not experience winter at all. Of roughly 400 species of birds that can be found at Londolozi, almost 60 of them are migratory. This includes various types of cuckoos, shrikes, eagles, waders and storks to mention a few. Just as the days begin to get shorter they set off on their journey northward. Some settle within Central Africa while others carry on a lot further and settle in Europe and even as far as Asia to enjoy the Northern Hemisphere’s summer while we endure the cold in the Southern Hemisphere.
Other animals, such as snakes, lizards, crocodiles and terrapins for example – all of which are cold-blooded, tend to alter their daily movements a fair amount. With the daylight hours being a lot shorter and the Sun travelling through a lower arc in the sky in winter, there is less overhead/direct sunlight each day. The cold-blooded animals will move into more exposed areas to take up the sun, using it to warm themselves.
Other cold-blooded animals such as certain species of frogs, enter a state of estivation. In this state, their metabolism is slowed right down which allows them to remain inactive for months. Most frogs are only active during warmer, wetter summer months when many temporary pans and watering holes fill up. This gives them a relatively short window of the year in which to mate and lay their eggs. Currently, there is a female foam nest frog nestled up outside my bedroom in the upper corner of my window frame. She has not moved in well over a month and is visibly alive and well. If left undisturbed, she will only become active again once the temperatures warm up and the onset of the summer rain is imminent.
For warm-blooded animals, the smaller ones at least, it is a relatively simple affair. Squirrels, mongooses, mice and genets for example have little burrows, crevices or holes where they will spend time resting and keeping warm. These smaller animals will spend less time each day being active, only coming out when they need to eat and forage.
Larger animals that don’t have burrows such as elephants, buffalo, rhinos etc. undergo more of a metabolic change in winter when their bodies will burn up fat reserves to produce heat. In most mammals, adipose tissue (which is essentially fat) is metabolized to create warmth within the body. This means that the more they eat, the more they secure the potential to create warmth. This is especially true for large predators like wild dogs, lions, leopards and cheetahs.
The dry, cold winter months tend to give the predators a slight advantage as prey can somewhat be weaker and easier to catch. This is very visible in browsing antelope such as nyala, bushbuck and kudu – their coats often lacking the lustre and sheen that they have in summer. It is harder for them to keep in peak physical condition in the winter because good browse becomes extremely sparse as most trees have lost their leaves, meaning that they don’t get optimum nutrition.
The following two images highlight the swing in food availability within the Summer and Winter respectively. The movement of elephants is heavily affected by the seasons. They rely on being able to consume large quantities of vegetation and therefore will move through areas where there is a permanent source of water. The Sand River, which retains a fair amount of lush greenery year-round, is what owes to Londolozi having many herds of elephants in the area over the dry winter months.
It is quite important to note though that most animals either have very thick skin or are covered in fur or feathers. This does make an enormous difference when it comes to the ability to insulate and retain body heat. This means that they do not feel the cold as much as we think they do.
An interesting observation that you can look out for in cold conditions is when an animal’s fur seems slightly raised or a bit ‘spikey’. This is known as piloerection. With the fur standing up, it traps an expanded layer of air that serves as insulation over the skin. The compound effect of this over the entire body makes a huge difference by helping the animal to retain heat. This is very much the same reason why birds ruffle up their feathers, giving themselves a ‘puffed-up’ appearance on a cold morning. It is naturally energy efficient too, allowing animals to adjust to the cold conditions of the environment without having to raise their metabolism.
One thing for sure is wild animals are extremely tough and hardy. The weaker ones have slowly been weeded out of gene pools over hundreds and hundreds of years.
Winter is always a great time to be in the bush and I am looking forward to the cooler weather.