Studies of rats and rat traps of Kerala

Abstract

In order to study the distribution of different species of rate in the State a detailed survey was conducted in different parts during the period from September 1978 to February 1979. Burrows of the various species were excavated to get detailed information on the special features of the burrow patterns. The findings of the present investigation are summarized below. It was found that 15 species of rats occur in Kerala. 1. Tatera indica cuvieri Of the four subspecies of Tatera indica, only T. indica cuvieri was present in Kerala. This species was distributed all over Kerala except in higher elevations like Wynad. The burrow system followed no specific patterns with a minimum of three openings. The emergency escape were concealed underneath. The burrowed out soil was expelled through a particular opening. More than one adult lived in a burrow system. 2. Rattus norvegicus This was a serious pest of paddy in Idukki district and Kuttanad and was mostly a field rat in Kerala. 3. Bandicota bengalensis bengalensis This species was more predominant in garden lands. Burrow were found extensive. Burrow entrances were concealed by heaps of soil. Food was found stored in the burrow system only in a few cases. Male and female rats lived in separate burrows. 4. Bandicota indica indica A field rat causing great damage to tuber crops. The burrow openings were larger in size than those of other species. The exit for removal of soil was always located on a higher point. Definite runways starting from the entrances were seen. 5. Mus platythrix The burrow openings of this mouse were encircled by pebbles. It lived in discarded burrows of other species of rats and not a fossorial type. 6. Mus saxicola Similar to M. platythrix in every aspect. 7. Mus booduga booduga It lived in small burrows in paddy fields and garden lands. The burrow system was always seen provided with one or more emergency escapes. 8. Mus cervicolor Found similar to M. booduga booduga in appearances, habits and habitats. 9. Mus musculus Found in houses and shops. 10. Rattus rattus Two subspecies were found in Kerala viz., R. rattus ruffescens and R.r. wroughtoni and the latter was found attacking coconuts. 11. Vandeleuria oleracea Found inhabiting trees and under grass growth around crop fields. 12. Golunda elliotti Found in forest and in thick grass growth around crop fields. 13. Millardia meltada meltada Seen in paddy fields in Wyanad, Calicut district. 14. Rattus raniiniae A new species of rat found in Trivandrum District. 15. Platacanthomys lasiurus A spiny rat damaging cashewnut in Idukki district. Study on indigenous rat traps. A total number of 17 indigenous rat traps were collected from various parts of Kerala. Among the various traps, Moncompu traps, for capturing rice field rats, bamboo-noose trap for trapping mole rat from live burrows, and the bamboo bow-trap for capturing rats infesting coconut crowns were found most useful.