Patterns of Social Behavior of Merriam's Canyon Lizard (Sceloporus M. merriami-Iguanidae)

Abstract

The social behavior of a group of 19 canyon lizards, Sceloporus merriami, was observed in a large enclosure. The pattern of movements and the cadence of these movements in the display sequence are species-specific. The domi- nant male is responsible for the majority of aggressive actions such as displaying, courting, fighting, and chasing in the group. Subordination is indicated by retreat, submission and reduced activity. Dominance was shared by two males, and when they were removed a new dominant male arose and maintained his dominance when the previous dominants were returned. A courting male nods rapidly while follow- ing a female and attempts to get a biting grip on the skin of her shoulder region to effect copulation. One observation suggests that the female may sometimes initiate courtship and mating. The canyon lizards observed in this study were captured in early April, 1960, along the canyon walls of the Devils River, 10 miles north- west of Del Rio, Val Verde County, Texas. They were kept in cages until early June and then released in an outdoor enclosure at the University of Oklahoma Biological Station in south-central Oklahoma. The square enclosure of galvanized sheet metal measured 10 feet on a side and was 3 feet high. The enclosed area contained fine sand vary- ing in depth from two inches near the sides to a one foot dune in the center. A row of six cinderblocks was stacked three, two, one along the top of the dune while stacks of two only were placed near three corners. A six foot by three inch pole was erected near one side and small pieces of wood were scattered over the area. Water was provided in a large sunken clay dish. Insect food was provided daily from sweep nettings. Other lizard species present in the enclosure included Scelo- porus woodi, Sceloporus graciosus, Sceloporus scalaris, Uta stansburi- ana, Urosaurus ornatus and Urosaurus graciosus. All individuals were color marked for individual recognition. Re- cording methods included still and movie photography and tape re- cordings. Observation periods were from 8:00 a.m. to 11:00 a.m. and 4:00 p.m. to 6:00 p.m., when the lizards were most active. Observa- tions began on June 10, when 19 canyon lizards (9 females, 10 male) were released into the enclosure, and continued on 25 different days until July 28 when observations were terminated.