Daily activities of water monitors (Varanus salvator macromaculatus Deraniyagala, 1944) in urban wetland, Bangkok, Thailand

By

Trivalairat, Poramad
Srikosamatara, Sompod

Type

Article

Date of Publication

2023-8-11

Original Publication

Herpetozoa

Volume

36

Pages

189--201

Subjects

Diet , Ethology , sex ratio , Squamata , Urban ecosystem , Varanidae

Contributed by

Pensoft Publishers

Language

English

Published by

Sofia, Bulgaria Pensoft Publishers

Identifiers

DOI: https://doi.org/10.3897/herpetozoa.36.e93492

 

Abstract

From July to October 2015, a study was conducted on the water monitors (Varanus salvator macromaculatus) at Dusit Zoo in Bangkok, Thailand. A total of 90 monitors were captured, measured for SVL, sexed, and marked on the right axilla. The captured monitors included 70 females and 20 males, resulting in a sex ratio of 3.5:1. Body size did not differ significantly between genders. The monitors exhibited bimodal diurnal activity, with a focus on fish hunting in the morning (06:00–08:00 h) and scavenging for fish leftovers in the afternoon (15:00–17:00 h). After the monitor lizards hunted for prey in the morning, they spent 5–7 hours basking and floating in the lake during the afternoon. Sexual behaviors were also occasionally observed. The monitors displayed frequent predatory behavior towards natural prey, especially fish, in the morning, as opposed to opportunistically scavenging on tourist food and fish leftovers observed throughout the day.