Ungulates areChordate，Vertebrate, Mammalia, Mammalia, a class of animals belonging to the order Chondrea and Artiodactyla.mammalMost of them have large bodies and slender limbs,toeHornyHoof, the number of hooves is not equal.The term ungulates has a wide but unclear meaning. It refers to ungulates that eat plants.In addition to these concepts, it is difficult to find the common characteristics of all ungulates.In fact, the word ungulates describes not so much the close kinship in zoology as the ecological adaptation in several parallel evolutionary branches. When you use this word, you must remember this fact.
The most obvious adaptation of ungulates is to change the teeth of chewing and grinding plants, the digestive tract that can transform a large number of plants into nutrients, and the limbs and feet that generally run on hard ground.In addition, many ungulates have horns on their heads as protective weapons, or some teeth are used for fighting or self-defense.Usually, but not all, this kind of mammals have closely arranged incisors. When they bite together, they form a slightly curved arc at the front of their heads.These teeth have the function of biting or cutting to collect leaves or grass into the mouth.Although there are useful canine teeth in some ungulates, generally speaking, canine teeth are missing in this kind of animals. If there are canine teeth, they also lose their shape and function.In some ungulates, canine teeth are linked to incisors to increase shearing function.However, the most obvious adaptation in ungulates is found in buccal teeth, which act like grinding a mortar in many ways.The crown surface of the molar is usually square or rectangular, which is due to the strong development of the upper molar's last cusp or some other cusps nearby, the disappearance of the lower anterior cusp and the formation of the tooth base. Therefore, the upper molar is equal to the lower molar's triangle in height and area.The original sharp tooth tip becomes a blunt point, ridge or ridge in the complex enamel fold.These changes increase the area of the crown.Many ungulates eat hard grass, and the height of their buccal tooth crowns increases, which is called the development of high crown teeth.With the increase of molar crown surface and tooth height, the total area of teeth that are beneficial to the research of mushroom plants in the life of animals has greatly increased.Finally, many hoofed premolars show "molarization", that is, the process of increasing and complicating the premolars. Therefore, usually small premolars become as large as molars, which increases the total area of tooth grinding.Of course, it is impossible to trace any trace of the digestive tract in the extinct ungulates.
A few ungulates have enlarged incisors or canine teeth to defend themselves, but the more common way is to develop weapons on the head.These may be horns, bone protrusions growing from the top of the head, which fall off and replace once a year;Or horn, a permanent bone protuberance, which is protected by cutin.
The most common form of self-defense in ungulates is fast running.Therefore, the limbs and feet of hoofed mammals have a significant growth trend.The growing legs increase the pace, enabling these animals to cross the ground quickly.This adaptation is to avoid the enemy;It also enables ungulates to find food in a larger area.
The ungulates usually walk with toe tips, which is called unguide.For this type of foot, the wrist and ankle are far away from the ground, such as the "knee" of the forelimb and the "hook" of the hind limb of the horse.Toes are often hoofed to protect feet and reduce vibration when running on hard ground.In many progressive ungulates, most of the functions of walking and running are borne by the middle toe, so there is a strong tendency of degeneration of the side toe.But in some ungulates, especially the large and bulky type, the feet are still short and wide, and the toes are little or no degradation.In this way, the foot becomes a wide structure, which serves as a wide foundation to support huge weight.
Some ungulates become semi aquatic or aquatic, so the feet and limbs also change[1]。
Ungulates
Announce
edit
Hoofed mammals are those mammals that feed on plants and have hooves.Its most prominent features are the teeth that are suitable for chewing and grinding plants, the digestive tract that can transform a large number of plants into nutrients, and the limbs and feet that run on hard ground.In addition, many ungulates have horns on their heads as protective weapons, and some teeth are used for fighting or self-defense.
Usually, this kind of mammal has closely arranged incisors, which form a slightly curved curve at the front of the head when biting together. They have the function of chewing or cutting, so as to collect leaves or grass for population.Generally speaking, canine teeth are missing in this kind of animals. If they exist, they also lose their shape and function.In some ungulates, canine teeth are linked to incisors to increase shearing function.The buccal teeth act like molars: the crown surface of the molars is often square or rectangular, which is due to the strong development of the upper molars' last cusp or some other cusps nearby, as well as the disappearance of the lower anterior cusp and the formation of the tooth base, so the upper molars are equal to the lower molars' triangular seats in height and area.The original sharp tooth tip becomes a blunt point, ridge or ridge in the complex enamel fold.These changes increase the area of the crown.Many ungulates eat hard grass, and the height of their buccal teeth crown increases, which is called the development of high crown teeth.With the increase of molar crown surface and tooth height, the total tooth area of grinding plants has greatly increased.Many hoofed premolars show a "molarization", that is, the process of premolar enlargement and complexity. Therefore, usually small premolars become as large as molars, which increases the total grinding area.
The most common form of self-defense in ungulates is fast running.Therefore, the limbs of hoofed mammals have a significant growth trend.
Ungulates usually walk with toe tips, which is called toe walking.This type of foot, the wrist and ankle are far away from the ground, and the toes often have hooves to protect the feet and reduce the vibration when running on hard ground.
In many progressive ungulates, most of the functions of walking and running are assumed by the middle toe, so the side toe has a strong tendency to degenerate.But in some ungulates, especially the large and bulky type, the feet are still short and wide, with little or no degradation of toes, as a broad foundation to support huge weight.Some ungulates become semi aquatic or aquatic, and their feet and limbs change accordingly[2]。
