How to distinguish frogs from toads?

Frog has two longitudinal folds from the back of eyes to the base of hind limbs, which are golden yellow or light brown. There is a faint longitudinal stripe in the middle. There are many rows of black stripes on the hind limbs. Frog's back is brown or yellow-green, and its abdomen is white. Toads have rough skin and are covered with warts of different sizes. The back is dark brown and the abdomen is milky yellow.

2. Observe that toad venom glands are rich, which can be divided into skin glands and retroauricular glands. Skin glands are distributed on the back of the body, and the epidermis is locally thickened into "wart granules". The posterior auricular gland is located above the cephalic tympanic membrane. Puncture the retroauricular gland carefully with a needle, and milky toxic serous fluid will flow out. Frogs have no poison glands.

3. Observe that the male frog has a pair of sound sacs behind his mouth. When vocalizing, the gas in the mouth is pressed into the vocal sac, making it swell into a ball, while the female frog has no vocal sac. Toads, on the other hand, have no voice sacs.

Compare teeth and tongue.

Frogs have a row of tiny maxillary teeth on the maxillary edge; There are also two parallel rows of small tumor-like protrusions on the vomer at the top of the mouth, which are called vomer teeth. On the other hand, toads have no teeth. Pull out the frog's tongue, its tip is forked; Toad's tongue is not forked.

5. Observe the connection between ureter and cloaca. The frog's two ureters are connected to the cloaca, and there are two openings in the wall of the cloaca. However, toad's two ureters first converge into a common ureter, and then enter the cloaca. There are only 1 openings in the cloacal wall.

6. Observe the connection between fallopian tube and cloaca. The frog's two fallopian tubes are also connected to the cloaca. Toads, on the other hand, fuse first and then communicate with cloaca.

Compare shoulder straps

The two upper coracoid bones of the frog are closely connected in parallel, do not overlap and cannot move alternately, which is called the fixed chest shoulder strap; On the other hand, the upper coracoid bones on both sides of toad overlap each other and can move alternately, which is called arc chest shoulder strap. In front of the inner ends of the two collarbones of the frog, there is a rod-shaped shoulder sternum, and there is a semicircular cartilage in front of the shoulder sternum, which is the upper sternum. Toad doesn't have these two bones.

8. Comparison of Vertebrate Frog The first seven vertebral bodies are all cylindrical, with concave front and convex back, which is called anterior concave type, and the eighth vertebral body is double concave type; However, the first eight vertebrae of toad are concave.

The cuticle of toad is keratinized, so it is drought-resistant and can move in a dry environment far from water. Although frogs and toads have different body colors, they have protective effects in different living environments, and there are great differences under the influence of the environment. The jumping ability of toad is far less than that of frog, but the poisonous glands protect it from being swallowed by carnivores to some extent. Such organs are protective organs. The male frog has a pair of vocal sacs, which are vocal organs. Frogs' maxillary teeth are all of the same type. These teeth have no chewing function, just to prevent small animals from slipping out of their mouths. The existence and position of teeth, whether the tip of the tongue is forked, and the types of shoulder straps and vertebral bodies are all the basis for the classification of tailless amphibians. The differences between the ureter, fallopian tube and cloaca of frogs and toads are often neglected in anatomy.