Expert of this article: Liu Yadan, former assistant secretary general/researcher of the Chinese Fisheries Society, and chief science communication expert in China
This article is reviewed by Zou Qiangjun, Chief of science popularization and publicity section of Beijing Aquatic Wildlife Rescue Center, senior engineer of science communication
The discovery of fossils is nothing particularly novel, but the discovery of a pair of fossilized turtles that are mating has to be shocking!
In Germany's well-known "Messer Fossil Pit", a turtle called "Allaeochelys crassesculptata" has died biologically about 47 million years ago, suddenly appearing in the form of fossils in front of the world's eyes, and is still in a state of mating!
Walter G. Joyce et al. / Biology Letters(2012)
How can it be judged that this pair of turtle fossils is mating? The scientists found that the males sandwiched their tails underneath the female mates, with the two tails aligned, which is consistent with the turtle's courtship status. It is also the first time in history that fossils of ancient turtles in a mating state have been found.
Know that mating is an instantaneous act and is the most difficult to record. Among the many fossils, only insects can be preserved when they are mated, and the sudden fall of pine resin seals them and becomes amber.
Seeing this, I think many people will ask: So how did all this happen? Look down and you'll know ↓↓
How can this pair of turtles remain mated?
Experts from the turtle fossil excavation site Ofser Lake Analysis, under normal circumstances, Allaeochelys crassesculptata turtle will mate in the shallow water of the lake, but there is volcanic activity at the bottom of the lake, toxic gases such as biogas, hydrogen sulfide suddenly erupted, when the turtle is mating can not swim, gradually sink to the bottom of the lake, inhaling toxic gases, resulting in death.
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But many creatures have disappeared after death, so what conditions does this have for the turtle to maintain such instantaneous behavior? There are external and internal causes in the analysis.
The external reason is that this lake is an inland lake, the water does not flow, and the body is not washed away; the second is that the turtle sank to a very deep lake bottom at that time, due to the lack of oxygen at the bottom of the lake, the body was not oxidized and decayed, and the sediment of millions of years was pressed on the corpse layer by layer, sealing them. The internal cause is that turtles' shells and bones are very hard, increasing the likelihood that they will become fossils after death.
What is its close relative, the pig-nosed turtle?
It is difficult for biologists to reveal too much information about biological behavior from biological fossils, and the study of the behavioral characteristics of biological fossils is more complicated, including through micro-fossils, burial, functional morphology and inbreeding comparison, some experts still choose inbreeding comparison. Throughout history, Allaeochelys crassesculptata's closest relative may have been a pig-nosed turtle whose scientific name is Carettochelys Insculpta.
The pig-nosed turtle is named after its resemblance to a pig's nose (if you only look at the nose, you think it is a swimming pig), and because it has two claws on its limbs, also known as the two-clawed turtle, it mainly lives in the waters around Australia and Papua New Guinea. Generally turtles are amphibians, but some are partial to land, while pig-nosed turtles are partial to aquatic turtles and do not like to go ashore, they are swimmers, and have a unique ability to swim backwards. In addition to spawning, he prefers to live in the water all year round.
Pig-nosed turtle Carettochelys Insculpta | Zou Qiangjun courtesy of photo
Although this turtle is timid and frightened, and likes to be in a dark corner, the pig-nosed turtle is the fighting turtle among the turtles, and the personality is grumpy. In the wild, we are not easy to watch battles, and in artificial breeding places such as the Amphibian Research Institute, we can often see turtles that bite and chase each other and are scarred, especially the hind edge of their dorsal carapace and tail are incomplete, and the tail vertebrae are exposed.
The breeding season for pig-nosed turtles is during the dry season, that is, between July and October. The embryonic dormancy period is what sets pig-nosed turtles apart. In the natural environment, after the embryos of the pig-nosed turtle mature, they will enter a dormant state in the eggs, waiting for the rainy season flood to bring them abundant food before the baby turtles break through.
Tortoises eat birds?
It is often heard that big birds eat small turtles, but last year there was a video report of a tortoise killing a small bird. This is an Aldabra tortoise that is eaten by a small tern chick. The tortoise eating the bird in the video is skilled and looks experienced. But scientists aren't sure whether predation on birds is a common behavior of tortoises, and can only speculate that the story is related to the human influence of the habitat's food chain.
Aldabrachelys gigantea, Aldabrachelys, | Mirko Schoenitz
However, although most turtles are quiet and slow, it does not mean that they are not agile in predation, and some turtles are very good at camouflage hunting, such as dead leaf turtles. This is a turtle with the strangest appearance, the head looks like a leaf, the shell is very angular, it looks like a piece of bark. The dead leaf turtle is also one of the oldest surviving reptiles, living in South America and being huge. Due to the special shape and size of the head, it cannot be shrunk into the shell, and it is not a shrunken head turtle!
Chelus fimbriatus |neil_mass
Are turtles endangered?
Nowadays, we are seeing pet turtles enter more and more people's homes, and it feels like turtles are common in life. But in fact, more than 60% of wild turtles have become endangered animals, scientific and technological personnel are working hard to carry out artificial breeding research and exploration, and the country has also set up many turtle sanctuaries, especially turtle sanctuaries. In addition, the state has been promoting efforts to protect the potentially extinct turtles and tortoises native to the mainland, such as the Release Action Plan for Shrews (2019-2035) released in April 2020.
Many turtles and turtles are protected animals that are prohibited from being caught and traded, and there are many turtles listed on the IUCN Red List of Threatened Species, such as concave tortoises and ground turtles, which are vulnerable species, and hawksbill turtles are listed as critically endangered species. Protected by the Convention on International Trade in Endangered Species of Wild Fauna and Flora, 104 species of aquatic turtles and turtles are listed in the CITES Appendix. Among the protected species promulgated by the mainland in 2020, there are 21 species of turtles and turtles, of which tortoises, sea turtles, shrews and turtles are first-class protected animals, and second-level protected animals include flat-breasted turtles, three-line closed-shell turtles, mountain turtles and other 11 species.
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In addition to strict conservation, artificial breeding studies are also an effective way to protect endangered species. In accordance with the relevant provisions of the Law of the People's Republic of China on the Protection of Wild Animals, the Ministry of Agriculture and Rural Affairs issued two batches of "Directory of Aquatic Wild Animals under National Key Protection for Artificial Breeding", including three-line closed-shell turtles, yellow-throated water turtles, flower turtles, black-necked turtles, Annan turtles, yellow-edged closed-shell turtles and black pond turtles.
Turtles and tortoises
It is an integral part of the ecosystem
Protect endangered and rare species
It is an important task to maintain the stability of the ecosystem
Let's work together to protect endangered animals
Together, we will protect the earth