Mating Ethogram of a Video-aided Study of Mating and Parturition in Captive Chinese Crocodile Lizards (Shinisaurus crocodilurus)

Mating behavior and parturition are important components in the life history of any species. The endangered Chinese crocodile lizard (Shinisaurus crocodilurus) is suffering dramatic population decreases in the wild. Successful captive breeding can provide individuals to be reintroduced into their natural habitat and help to restore the wild populations. Studying the mating behavior and parturition of these lizards in captivity will enable us understand how is this ancient species reproduction and optimize artificial reproduction protocol. We studied the mating behavior and parturition of Chinese crocodile lizards in captivity using video recordings at the Daguishan National Nature Reserve, China, from 2015 to 2017. We analyzed pre-copulation and copulation, which occurred in mid-March to late May from all studied years. Pre-copulation and copulation lasted on average 7.51 (n = 11) and 27.45 (n = 11) minutes, respectively. We found that large-bodied male lizards have longer copulation periods, a pattern seen in other lizard species. In the mating event, males always initiated sex, while the females were passive. The duration of parturition lasted 153.8 +/- 26.8 (n = 46) minutes, and larger females had heavier clutches. In addition, even though Chinese crocodile lizards represent an ancient lizard Glade with primitive characteristics, they still abide by the reproduction patterns seen in most other lizard species.