At Christmas, deer suddenly become very popular animals. As well as seeing deer on cards and decorations, local residents may also observe real deer that have escaped from deer farms, occasionally wandering over Tamborine Mountain, and the surrounding foothills.
Deer are a family of hoofed mammals inhabiting a wide variety of habitats with a wide geographical distribution. They are athletic, lithe, with strong legs for jumping and running, smaller species may weigh around 40 kg while larger species such as elk and moose may reach 200 kg. In most deer species only males have solid, bony, branched antlers which they shed and grow every year. Deer may resemble other horned species such as antelope, but in these species male and female have hollow horns, which are retained permanently.
Deer are among the 150 domestic and wild species that are described as ruminants, they have a stomach with four compartments. The four parts are the rumen, reticulum, omasum, and abomasum. This complex digestive system is required to digest the fibrous cellulite in plant material. The plant material is usually consumed quickly and swallowed. In the rumen the plant matter mixes with saliva and begins the fermentation process that occurs through the action of billions of microorganisms such as bacteria, protozoa and fungi. A bolus of semi digested food, known as cud, is regurgitated. The animal chews the cud, which reduces the particle size and makes it easier to digest. After passing through the rumen and reticulum the digested material moves into the omasum, then the abomasum which is the "true" stomach of the ruminant. It has a similar function as the stomach of a non-ruminant and secretes enzymes and acids to break down food into nutrients.
Reindeer have a circumpolar distribution over the tundra and taiga in Eurasia and North America, where they are known as caribou. In Europe there are wild and domestic reindeer. Reindeer have been domesticated for about 3000 years, they are used for milk, hide, meat and as a beast of burden which can pull up to twice its weight. Reindeer are the only deer that have been domesticated and this has been possible because they are good-natured, will reproduce in captivity, and have a well-developed social structure that allows coexistence in high population densities.
In North America caribou are wild. They are found in herds from 20 to many thousands. Their blood circulation, thick fur and undercoat, broad hooves, snow shovelling head and acute sense of smell are some of their adaptations to the harsh cold and snowy conditions. They travel huge distances because of weather and to find food, they may cover 5,000 kms in a year at a rate of 19-55 kms per day. They can run at speeds of 60 to 80 km/hour and can swim at speeds of up to 10km/hour. Unfortunately caribou are under threat from extensive hunting, habitat loss and the creation of large dams which obstruct their migration routes.