Leopard cat publication update 2015 to 2017

Some leopard cat publications were out in the last two years, and I try to keep track of as many as possible. Some quick thoughts and summary:

Nakanishi & Izawa took a look at the importance of frogs in the diet of the leopard cats from Iriomote Island, Japan. I must say that the Japanese are the gold standard in leopard cat species biology work with the population on Iriomote Island. They examined the stomach contents and compared the results to scat analysis, which is traditionally more frequently used as it is less invasive. Frogs appeared to be important, but under represented compared to scat studies.

Meanwhile. Srivathsa et al. were one of the first to use camera traps to estimate leopard cat population density in India. The density in in forests there appear to be similar to Sabah, but below what we have on Pulau Tekong, Singapore.

Going back about 5,000 years ago, it seems that leopard cats had some close interaction or relationship with Neolithic people in China. The authors (Vigne et al.) use the term “domestic”, but I’ll hesitate to do so in the strict sense of the word.

And finally, a molecular phylogeography of the leopard cat sampled across its global distribution. Rather important that this is done, and the coverage is quite admirable. I cannot say the results are unexpected though (see image below).

Distribution of leopard cat subspecies suggested by Patel et al. (2017). Image from paper.

Arjun Srivathsa, Ravishankar Parameshwaran, Sushma Sharma, K. Ullas Karanth. (2015) Estimating population sizes of leopard cats in the Western Ghats using camera surveys. Journal of Mammalogy 96(4): 742-750. doi: 10.1093/jmammal/gyv079

Nakanishi, N. & Izawa, M. (2016) Importance of frogs in the diet of the Iriomote cat based on stomach content analysis. Mammal Research 61: 35. doi:10.1007/s13364-015-0246-9

Riddhi P. Patel, Saskia Wutke, Dorina Lenz, Shomita Mukherjee, Uma Ramakrishnan, Géraldine Veron, Jörns Fickel, Andreas Wilting, Daniel W. Förster. (2017) Genetic Structure and Phylogeography of the Leopard Cat (Prionailurus bengalensis) Inferred from Mitochondrial Genomes. J Hered 2017 esx017. doi: 10.1093/jhered/esx017

Vigne J-D, Evin A, Cucchi T, Dai L, Yu C, Hu S, et al. (2016) Earliest “Domestic” Cats in China Identified as Leopard Cat (Prionailurus bengalensis). PLoS ONE 11(1): e0147295. https://doi.org/10.1371/journal.pone.0147295

Crowdsourcing: Make no bones about it

This leap frogs a few Doing the dirty job posts, but I think the following story is worth sharing and compelling enough to stand on its own.

Right now, I have extracted DNA from the collected scats, analysed the genetic information, and moved on to washing out the scats for prey remains to determine the diet of leopard cats in Singapore. Most of the remains are hair, bones, feathers, scales and exoskeleton.

A day in the office: typical crime scene.

However, here comes the problem: I belong to the generation of biologists with comparative anatomy and mophology swapped out from our curriculum in favour of cell biology and molecular genetics — therefore, not too good at identifying animal bits at all. To compensate though, I did a fair bit of reading up on hair and skeleton before starting.

Bones are a little more tricky than hair (which I have a reference collection of), but excellent diagrams help a lot. Every now and then, strange things pop up, but are usually relatively easy to resolve.

After more than 30 samples, something odd appeared that I have yet to encounter. It was a bone fragment that looked like a product of two fused bones. Unfortunately, it was not complete, otherwise it may have been easier to identify. So there it started: the case of the mystery bone.

I had my suspicions of what it may be, but I also needed to know where to look and had no comparative material for skeletons. The Raffles Museum of Biodiversity Research collection is closed to prepare for the move to its new premises, and I did not want to be a nuisance to the collections manager. So, knowing that Twitterverse is full of accomplished workers in the field of science, I decided to try crowdsourcing to get more experienced/expert opinion in bone identification:

In a nutshell, I must say I was humbled by the responses and the helpful scientists on twitter.  Full story and final reveal on the mysterious bone below.

N.B.: Some tweets may have been lost if tags have been changed or if they are of a different time series.

Read more

Doing the dirty job – part 1

Tracking rare and elusive wild carnivores can be challenging as there are not that many of them to begin with and they are mostly shy and tend to move about a lot. Fortunately, there is an easier way to study these animals as they tend to leave behind clues of their presence which tend to be more permanent. One important clue I seek out is scat, i.e. their droppings.

Other than a sign post that says “I was here”, scats are after all, the end products of digestion and can reveal what an animal has been eating. Although it is not as as clear as looking at stomach contents like what I did in my previous post, undigested remains such as bones, hair and feathers can still be used to identify the food items. Furthermore, the surface of each piece of scat may have rubbed off an animal’s digestive tract and picked up cells on the way out. These cells contain DNA which when extracted and analysed, can be used to identify species (with an algorithm called BLAST) and individuals.

Fuzzy bits of fur can be seen coming off the scat.

It is not difficult to identify leopard cat scats in the field as they tend to lay them along the trails, possibly for scent/territorial marking purposes. Like domestic cat droppings, they are typically about 1.5 to 2 cm in diameter and around 10 to 15 cm long, sometimes in fragmented pieces. One end is usually rounded, and the other ends in a pointy twirl, often with some hair.

There are usually no plant parts, but sometimes a bit of grass are present.

Fresh leopard cat scat usually appears to be in various shades of brown and have a distinctive musky smell. Old scats turn white due to the amount of calcium present.

Aged white scat.

Scat that is found is collected in a sealable plastic bag and then frozen at -80o C to preserve the DNA. I cannot wait to start analysis on the 33 pieces of scat that I have amassed since the start of the project.

Other researchers in Singapore who have been successful with finding out more about diet or genetics with scat are those done on the common palm civetsmooth-coated otter and banded leaf monkey.