If you have ever seen a deer or horse chewing their food then you may have noticed that they eat with a sidewards motion. I wanted to find out about the teeth that herbivores have and what I found was really interesting.
Herbivores are animals that primarily eat plants as their main diet. Plants wear out teeth much faster than meat. Plants are not as nutritious as meat, so herbivores need to spend longer feeding. Unfortunately, this means that their teeth do not last as long as carnivores.
Herbivores have incisors that cut the plant before it is chewed by the molars. Some species also have canine teeth as well.
Many herbivores eat grass which contains silica salts in the leaves and stems. The salt is damaging to the teeth as it wears them down when the animal is chewing.
Teeth are covered in enamel and herbivore quickly grinds down the enamel leaving the dentine underneath exposed. Carnivores do not have this problem as the enamel stays intact. Dentine wears down at a quicker rate than enamel with the enamel appearing as ridges.
Herbivores use their incisors to bite of the plant before the molars chew and grind it before swallowing. Herbivores have two different sets of teeth; the incisors are known as the biting teeth and the molars the chewing teeth. The two sets of teeth are separated by a diastema, a small gap.
Many different animals have different ways of eating. In this article I look at a few of these.
Horses have the most teeth out of all herbivores. Horses and ponies have up to 40 teeth with 6 incisors along the top of the jaw used to cut the grass by biting against the incisors in the lower jaw.
Although slow, the grazing that a horse does in its lifetime does wear the enamel down revealing the dentine.
Horses chew grass at the back of their mouth using molars. The molars are long with ridges of enamel above the dentine and glue. The glue not only keeps the root where it should be but also fills any crevices and gaps in the sides of the molars.
If you have seen a horse chew then you will know that they chew in a sideways motion. Horses grind their molars against each other to break down the plant cells. Once the cells are broken down, the animal’s saliva and digestive juices help to break down the plant so that the nutrients are ingested.
Male horses also have some teeth that females do not. These are used when fighting for females in mating season and these canine teeth are used to bite other males.
Deer and some other ungulates aid their digestion by effectively chewing their food twice to get all the nutrients. As with horses, deer use their incisors to cut the plant material, although the incisors are only along the lower jaw. Deer have a pad in the top jaw which helps to reduce wear on the incisors when eating
Deer have three incisors on each side of the lower jaw and also a canine. The canine is not used for fighting as in horses but helps to cut plant material. Fallow and roe deer do not have the extra canine on each side of the lower jaw. Deer have 12 molars which they use to grind plants.
Smaller mammals have incisors and molars but they do not eat plants in the same way that deer do. Rabbits, hares, and rodents do not have any canine teeth. The dentine quickly wears out keeping the incisors short as they only have enamel on the front edge.
Although the incisors wear out quickly they also grow at the same rate. Rats, for example, grow their incisors up to 6 inches a year, but also have fewer teeth than most other mammals except mice and voles.
All herbivores can move their jaws in a sidewards motion which helps them to eat. Carnivores can only bite up and down, not side to side. Larger herbivores such as deer need to eat a huge amount of grass and plants to survive, and chewing sidewards allows them to chew quickly before swallowing. This allows them to eat quicker when in the open and exposed to potential predators.
Later, when the deer is not in an exposed position, they will regurgitate the plant also known as cud. By giving the plant another chew before swallowing the animal is making sure it gets all the necessary nutrients from the plant. This is known as chewing the cud.