Crocodile lizard
【Animal Profile】:
Crocodile lizard (scientific name: Shinisaurus crocodilurus): is a reptile in the family Crocodidiadae, the crocodile lizard. It is a relatively ancient type of reptile, with a body length of 15-30 cm, a tail length of about 23 cm, a weight of 50-100 grams, and the body can be divided into 5 parts: head, neck, trunk, limbs and tail. The head is high, the head and body shape are similar to lizards, and the part below the neck, especially the side-flattened tail, has both prismatic scales and many black broad horizontal stripes, which are very similar to Yangzi crocodiles, so they are called crocodile lizards.
Living in puddles of stagnant water in mountain streams, active in the morning and dusk, sleeping soundly on thin branches during the day, jumping into the water immediately after being frightened. Reproduction occurs in June-August of each year, ovoviviparous, and hibernation from November to March. The diet is mainly insects, but also tadpoles, frogs, small fish, and worms. Produced in Dayao Mountain in Guangxi and Vietnam, Yaoshan crocodile lizard is a Chinese specialty.
【Morphological characteristics】:
The crocodile lizard is olive-brown with pale sides, dyed pink or orange with dark spots, dark transverse stripes from the back to the end of the tail, and a milky white ventral surface with pink or orange edges. The tip of the head is pointed, the back part is square, slightly quadrangular pyramidal, the top is flat, flat with inconspicuous fine scales, the scales near the end of the snout are larger, and there is a prominent milky white dot in the center of the top of the skull, called the parietal eye. The mouth is wide, with 1 tongue inside, 1 pair of internal nostrils, and a larynx in the pharynx. The edges of the jaw are densely covered with homotypic fine teeth. The tongue is fleshy, very fat, black at the apex, and shallowly forked. The eyes are medium-sized, the pupils are round, there are golden circles around the holes, and there are also movable upper and lower eyes and faces and transparent transient membranes. At the back of the eye, there is a pronounced tympanic membrane in front of the cervical sulcus on the side of the head. The lateral part of the head radiates 8 dark streaks from the eyes, 1 long behind the eye, 3 thicker under the eyes, irregular black streaks on the back end of the body, and short black markings on the ventral surface. The tail has 11-12 black and brownish-green transverse stripes, each occupying 2 segments.
The neck is conspicuous and separated from the head by a distinct longitudinal groove, and there are several rows of larger raised prismatic scales on the posterior dorsal surface of the cervical sulcus, with granular small scales sandwiched in the middle, and the lateral scales of the neck are semi-thin, gray, yellow, pink, and there is a prominent round dark spot on the upper anterior side of the neck of the forelimbs. The dorsal and ventral sides are slightly flattened, and the dorsal scales are fewer, only the granular fine scales are scattered between the large prismatic scales, and the prismatic scales are arranged approximately vertically on the back of the body and extend to the tail, and to the hindlimbs they form a regular two-row arrangement on both sides of the tail. There are 6 to 7 dark black broad transverse stripes on the back of the body, and the transverse stripes are divided into two when they reach the side of the body, and are pink red between the forked transverse stripes, and the red perimeter is black. The lateral sides of the body near the ventral surface of older individuals are generally pink, orange, and interspersed with black ridge-like scales.
The tail is flattened laterally, with longitudinally arranged large prismatic scales on each side of the back of the tail, concave in the middle like a deep groove, and the pike-like scales are wider at the base of the tail, and gradually narrow when extended towards the tail, but do not converge. The tail has a distinct segmentation of about 35 segments, with one ridge-like scale on the dorsal side of each of the first 13 segments and 2 in each of the last 20 segments. There are 8 ridges on the caudal and ventral surfaces that extend towards the caudal end. The tail has 10-11 dark black horizontal stripes, the whole body has 16 broad stripes, 5 on the trunk, the boundaries of the chest and abdomen are not obvious, and the horizontal stripes in older individuals are slightly pink.
The crocodile lizard has thick limbs and thin claws at the ends of its toes. The upper arms of the forelimbs are slightly shorter than the forearms, olive brown, and densely covered with protruding granular scales on the side of the body, and are yellowish-white in color. There are several rows of small scales on the back of the fingers, arranged in a "human" shape, and the long order of the fingers is 4, 3, 2, 5, 1. The upper and lower segments of the hind limbs are almost equal in length, and the order of toe length is 1, 3, 5, 2, 1. The hind limbs later have transverse lobe-like cloacal holes, the surrounding scales are square, there are 2 junctional sacs in the male cloaca, and there is a pair of gonads in both male and female cloaca, and the opening is at the outer edge of the cloaca, which can secrete a special odor of liquid.
Crocodile lizards are naturally inactive, locals like to call them "big sleeping snakes", they can go a month without eating or drinking without affecting their survival.
【Habitat】:
Crocodile lizards inhabit ravines below 760 meters above sea level, and are generally puddles with small streams. The surrounding rocks are rugged and bushy, and the leaf margins are mostly zigzag-shaped, similar to the lack of carvings on the tail of crocodile lizards. The ravines are wet and the rocks and trunks are similar in color to those of crocodile lizards. These provide a good hiding effect for crocodile lizards to hide inside.
【Life habits】:
Crocodile lizards mostly rest at night on branches with a height of about 1 meter above the surface of the water and a diameter of 3-7 cm. Whether it is on a raised branch or a drooping branch, it is also called the "big sleeping snake" by prostrate its head to the sky, clinging its limbs to the trunk, closing its eyes, motionless, and caressing its back without touching the branch. However, if the branch is touched, it will immediately roll over and fall into a puddle to hide, diving for up to 20 minutes, and then snouting the exposed water to ventilate, or hiding under a stone cave or tree roots, so it is also known as "drowning dog".
He is rarely active, and comes out early in the morning and evening to move and forage. Food includes tadpoles, frogs, small fish, worms and insects. After discovering the prey, he agitated his eyelids, extended his small tongue, quietly approached the prey, and then quickly pounced, biting the prey with his mouth, and then slowly swallowing the prey whole. The tail can regenerate , but the regenerated tail is shorter, rounded , black , with small scales , but no ridge , and no toothed edges. Although it is not flexible enough, it can prey on terrestrial earthworms, locusts, aquatic tadpoles, small fish, etc. The forelimbs play an auxiliary role in predation. Hibernate in winter hidden in tree holes or rock crevices.
【Distribution range】:
It is found in China (Guangdong, Guangxi, Hunan may become extinct) and Vietnam.
It is a special species in China, and it is very special in geographical distribution, and China has recently found crocodile lizards in Pingzhu, Luolian, Luo Dan, Luoxiang, Qiongwu Brigade in Lisong Township, Hezhou City, Jiulong Township, Beituo Township, Zhaoping Jiulong Township, Beituo Township and Luoxiang Township in Jinxiu Yao Autonomous County, as well as in Luokeng Town, Qujiang, Shaoguan, Guangdong, and the crocodile lizard found in Dayao Mountain in Guangxi is also known as Yaoshan crocodile lizard. The crocodile lizard is endemic to China and neighboring Vietnam. Eight known subgroups exist in China from Guangxi Province (Guiping, Hezhou, Jinxiu, Zhaoping and Mengshan Counties) and Luokeng Nature Reserve (Qujiang County) in Guangdong.
Species from northern Vietnam were first reported in 2003; In this country, crocodile lizards are still known only on the eastern and western slopes of Yen Tu Mountain (Bac Giang and Quang Ninh provinces), more than 500 kilometers from the nearest Chinese region, and the Vietnamese subpopulation itself is thought to be scattered. The altitude range of this species is 200-1,500 meters. In Vietnam, it was recorded from a more restricted altitude zone between 400-800 meters above sea level.
【Breeding method】:
Males and females are not easy to distinguish from characteristics such as stains, but males have more large spots and more vivid spots. If the tail base is strongly pressed after capture, a pair of short and thick meat sticks will appear from the cloaca hole, which is its male mating organ and can undergo in vivo fertilization. Around August is the breeding season, ovoviviparous, 4 to 8 litters per birth. During the breeding period, males show strong courtship behavior, chase females, and constantly support the body with their forelimbs in front of the female, swing their heads, appear extremely excited, and chirp, and then quickly bite the left abdomen of the female with their mouths, forcing the female to turn the back of the body over just so that its cloaca gland hole is opposite the male adapter, and then carry out mating, about 20 minutes of handover, and then separate.
The crocodile lizard is an ovoviviparous animal that mates in August each year, after which the fertilized egg develops in the female, but does not draw nutrients from the mother, and the gestation period is 9-10 months. When temperatures rise in May and June of the following year, pregnant female crocodile lizards awaken from hibernation and begin giving birth. Sometimes litters are laid on land, sometimes in water, with 4-8 litters laid within 1-2 days, and unfertilized eggs are also laid at litter time.
The newborn juvenile is 10.5-13 cm long and weighs 2.7-4.5 grams, and the morphology is almost exactly similar to the adult, except that the body color is slightly darker, especially there is a distinct triangular tender yellow spot on the top of the head, which does not disappear until about 9 months, followed by the eardrum. Juveniles feed on their own after 10 days of birth and prefer to move alone, often lying high on rocks or in the tips of tree branches near water. It feeds on live animals such as small fish, earthworms, tadpoles and insects. There is a phenomenon of competing with each other when eating. The way of feeding is also similar to that of adults. You can dive, but usually no more than 5 minutes, and adults can dive for 10 minutes to half an hour. In addition, larvae are more sensitive to external stimuli, especially temperature changes, than adults. Once frightened, they quickly jump into the water and hide. It grows rapidly from birth to October, and then enters the hibernation period. Sexual maturity is reached at the age of 3.5-4 years.
Crocodile lizard production peaks from March to May every year. In April 2022, at the Crocodile Lizard Rescue and Breeding Center of Guangxi Daguishan Crocodile Lizard National Nature Reserve in Hezhou City, a female crocodile lizard gave birth to 14 healthy crocodile lizard babies one after another, becoming the "hero mother" who gave birth to the most crocodile lizards in a single houset.
【Protection Level】:
Listed on the IUCN Red List of Threatened Species (IUCN) 2014 ver3.1 - Endangered.
Listed in Appendices I, II and III of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) 2019 Appendix II.
It was listed in the list of wild animals under national key protection (February 1, 2021) at the first level.