Felis chaus kelaarti the southern sub species.
This is one of the largest jungle cats I have seen and was almost the size of a street dog. They are common in the country side although mostly nocturnal and sightings will be fleeting. One of the colloquial names of the Jungle cat in malayalam in North Malabar is Naya-kallan (translates to ‘dog thief’). Although it is doubtful if a jungle cat will attack an adult dog they are very likely to predate on pups and sub adults. Many of the older generation whom I checked with confirm this.
An interesting dimension which I came across on the net which affects the size of animals within the same genus across geographic locations is supposed to be competition from other species of the same genus –Intraspecific competition. The presence of a variety of small felids can also affect the size of jungle cats as compared to those in a geographically different location where such variety is lower or absent. The article in the below link gives a detailed description of the ecology of this common but shy and enigmatic predator.
500D, 55-250, 250mm, AE, f5.6, ISO 400, SS 1/80 Cropped image. Shot late in the evening in low light. C&C welcome