Herbivores are animals that survive on a strictly plant-based diet. Unlike carnivores that eat other animals, herbivores only consume plant matter. Some common herbivores include ungulates like deer, cows, zebras, and horses, as well as rodents like rabbits, porcupines, chinchillas, and capybaras. There are also herbivorous marsupials like koalas and kangaroos. Even some species of lizards, turtles and fish are herbivores.
Herbivores consume all different parts of plants including stems, leaves, shoots, roots, bark, and plant reproductive parts like fruits, seeds, and flowers. Different herbivores have adapted to eat certain plants that are accessible in their native habitats and environments. For example:
- Deer mostly consume leafy greens, twigs, bark, branches, fruit, fungi, and forbs like clover or violet.
- Cows mainly eat grasses, hay, silage, and cereal grains like barley or corn.
- Horses graze primarily on grasses, sedges, and other pasture plants like clover. They also eat hay and grain concentrates.
- Rabbits mostly eat grass, clover, wildflowers, vegetable plants, fruits, roots, and tree bark.
- Koalas feed almost exclusively on eucalyptus leaves and bark.
- Elephants eat grasses, tree foliage and plants like vine leaves, shrubs, roots, and bark.
Why do herbivores need specialized teeth?
Herbivores have evolved specialized teeth compared to carnivores to help them efficiently process and digest fibrous plant matter. There are several important reasons herbivores benefit from different types of teeth:
- Plants are difficult to digest – Leaves, grasses, tree bark and woody stems contain a lot of cellulose, lignin and other compounds that make them high in fiber but low in nutrients. The cell walls in plants are tough to breakdown. Herbivores need teeth designed for grinding and shearing plant matter to help digest it.
- Plants don’t run away – Since plants are rooted in place, herbivores don’t need sharp teeth to seize and kill evasive prey. Their teeth are more efficient for grinding and chewing stationary plant matter.
- Plants regrow and replenish – After grazing, plants will continue to regrow allowing herbivores to return and eat again. The teeth of herbivores are made for grinding down plant matter continuously over a lifetime.
- Protection from predators – The teeth of herbivores are not well suited for attacking or tearing flesh. However, herbivores are prey for many carnivores. Their plant-based diet and teeth help them avoid conflict and escape predators.
- Varied abrasiveness – Different plant matter has varied abrasiveness. Grasses are very abrasive due to silica particles while leaves and fruits are less abrasive. Herbivores benefit from having durable teeth that resist wear from abrasives.
- Regional plant adaptations – Based on the native vegetation in different regions, herbivores have adapted teeth structures to specialize in consuming certain plants. For example, giant pandas have strong molars for chewing thick bamboo.
Do herbivores tend to have flat teeth?
Yes, herbivores tend to have relatively flat teeth compared to the pointed, blade-like teeth seen in carnivores. The broad, flattened surfaces allow herbivores to effectively grind and chew plant matter between opposing teeth.
Grinding molars – The molars in the rear of the mouth generally have wide chewing surfaces and ridges or cusps for grinding. Cows have broad ridged molars for chewing cud while horses have long, deep molars for pulverizing grasses and hay.
Flattened premolars – Herbivores usually have some premolars alongside their molars to assist in grinding food. However, their premolars have flattened edges rather than sharp points and blades.
Wide incisors – The front incisors in herbivores are generally wider and flatter than the incisors of carnivores. This allows them to bite off and shear pieces of plant matter.
No canines – Herbivores lack the long, pointed canine teeth that carnivores use to seize, kill, and tear meat. They have no use for sharp canines to hunt prey.
Some examples:
- Cows – Broad, ridged molars for grinding, wide incisors for biting off plants
- Horses – Prominent flat incisors for clipping grasses, deep flat molars for grinding
- Rodents – Constantly growing flat incisors for gnawing, flat molars for grinding
- Elephants – Sequential wide, ridged molars that get pushed forward and wear down over time
Are herbivore teeth very strong?
Yes, in addition to being flat, the teeth of herbivores also tend to be extremely durable and strong compared to carnivore teeth. Their strength helps compensate for their plant-based diet:
- Silica in grasses – Grasses and some other plants contain silica particles which quickly abrade and wear down teeth if they are not sufficiently strong. Grazers like cows and horses have especially durable tooth enamel.
- Constant chewing – Herbivores spend most of their waking time grazing, browsing, and chewing. The near-continuous mechanical forces strengthen teeth roots and enamel.
- Coarse vegetation – Bark, branches, stems and some leaves are extremely fibrous, stringy and coarse. The teeth of herbivores like elephants can endure a lifetime of grinding down this rough material.
- Avoiding fractures – The incisors of rodents are very prone to fracture from gnawing all day long. But they have extremely hard enamel to withstand compressive and shear stresses.
- Regrowing teeth – The constantly growing incisors and molars of rodents wear down quickly, but they regrow continuously to remain functional throughout life.
- Delayed replacement – Elephants have 6 sets of molars over their lifetime. Each set is massive and gets slowly pushed forward as it wears down from coarse vegetation. The slow replacement cycle saves energy.
- Deep stable roots – In addition to durable enamel, horses and elephants have deep tooth roots to provide stability during grinding. This adds strength despite the constant forces.
How do herbivore teeth compare to carnivore teeth?
There are major structural differences between the teeth of herbivores which are made for grinding plants and teeth of carnivores which are adapted for consuming meat:
Herbivores
- Broad molars and premolars with flat chewing surfaces
- Ridges, cusps, and high crowns on molars to pulverize plant matter
- Durable enamel resistant to abrasion from silica and grit
- Flatter wider incisors for biting off vegetation instead of pointed ripping teeth
- No long canine teeth since they are not needed for attacking prey
Carnivores
- Very sharp, pointed incisors and long canines to seize prey
- Carnassials and blade-like premolars to slice through flesh and hide
- Lower shorter tooth crowns since they do not need to grind food
- Scissor-like occlusion for slicing meat instead of crushing grind
- Little enamel since their diet is not abrasive
In summary, herbivores are optimized for grinding and crushing coarse plant material while carnivores are optimized for piercing, slicing, and shearing meat. This is reflected in huge differences in their tooth design.
Do some herbivores have unique tooth adaptations?
Some specialized herbivores have evolved very unique tooth structures and designs to help them thrive on specific plants:
- Giant pandas – To crush thick bamboo, pandas have very large, heavy molars and an extra bone that reinforces their jaw and skull.
- Koalas – Koalas have ridged teeth to finely shred the fibrous eucalyptus leaves they specialize in. Their enlarged molars distribute chewing forces.
- Sumatran rhinos – These rhinos have pointed lip extensions that help them grasp leaves and twigs to bite off plant matter since they lack front incisors.
- Manatees – Manatees completely lack enamel on their molars. Their teeth are continually replaced as they wear down from grinding aquatic plants.
- Fruit bats – Ridges on their cheek teeth help fruit bats slice through thick fruit pulps and rinds while incisors pierce hard seeds and nuts.
- Leaf-cutter ants – Leaf-cutters have serrated mandible edges that function like scissors to precisely cut sections of leaves for carrying.
Specialization for regional vegetation is key to how herbivores evolved unique dental adaptations to their diet. But grinding functionality remains essential.
Frequently Asked Questions
Q: Which herbivore has the largest teeth?
A: The hippopotamus has the largest canine and molar teeth of any herbivore. Their lower canines can reach nearly 16 inches (40 cm) long. Hippo molars can also be up to 5 inches (12 cm) in length. These oversized teeth help hippos forage on and graze grass near the aquatic habitats where they live.
Q: Do any herbivores have tusks?
A: Yes, several herbivores possess long protruding tusks including elephants, wild boars, warthogs, and ancient extinct species like woolly mammoths, giant ground sloths, and mastodons. In elephants, the tusks are modified enlarged incisors. Elephants use their prominent tusks for digging up roots, stripping bark to eat, self-defense, excavating water, and scraping salt licks.
Q: How many teeth do cows have?
A: Cows have a total set of 32 permanent teeth as adults. They lack upper front incisors but have 8 permanent incisors on the bottom front. Cows have 6 strongly ridged premolars and molars on the upper and lower jaws on each side for a total of 24 cheek teeth. These premolars and molars are responsible for the grinding and chewing of cud.
Q: Do rabbits teeth ever stop growing?
A: No, rabbit teeth grow continuously throughout their lifetime. Their incisors and cheek teeth grow at an average rate of 3 to 5 mm per week. This allows rabbits to maintain functional teeth as they get worn down from daily gnawing and chewing abrasive grasses, roots, and bark. The nonstop growth prevents excessive wear that would lead to malnutrition.
Q: How do herbivores chew without canine teeth?
A: Although herbivores lack the long, sharp upper and lower canine teeth that carnivores use to stab and tear meat, herbivores have wide premolars that align and function similarly to canines for chewing. The broad opposing surfaces of their cheek teeth allow herbivores to grind food. Many herbivores also chew in a rotating circular motion which helps wear down teeth evenly as they break down plant matter.
