Sperm storage or parthenogenesis in Crocodylus moreletii

A few years ago, I published an account of long term sperm storage in the Ganges softshell turtle (Nilssonia gangetica), with females producing eggs for 15 years without access to a male. Turtles have seminiferous tubules, which are structures that allow for this incredible "immaculate conception".

Last week, one of our Morolett's crocodile female laid 36 eggs. She had been in isolation since May 2007, since she didn't get along with the breeding group, and was repeatedly attacked by the single male. So we collected the eggs, and found that two of the eggs were banded!!! This is a little over three years of sperm storage in a crocodile, as far as I know only reported in the dwarf caiman (Paleosuchus palpebrosus), and the American alligator (Alligator mississippiensis), although the later don't store sperm for more than a year.

The interesting factor is that female 204 (the Morolett's female of concern), laid clutches in 2007, 2008, and 2009, but none of these eggs were fertile. Anyhow, we are taking very special care of those 2 viable eggs and hope to hatch them, after which we can perhaps tell by blood samples from them, female 204, and the male, whether this is a case of sperm storage or parthenogenesis.

Mugger attack on dog on the Rapti River, Nepal

http://il.youtube.com/watch?v=e-SxH4TOjz8

This is one incredible video, of a mugger cruising up to a dog cooling itself in the water, and blatantly (I say blatantly because there's about 10-15 guys watching it all happen) grabbing the canine and dissapearing with it. Everyone is having a good laugh following this attack on the video, which is interesting. Patrick and I discussed this during our tea break today, and were thinking that this is the "worst" kind of behavior for a croc to exhibit, viz a viz human crocodile conflict. There is no launching out of the water suddenly, no "sighting" the target several times as the croc moves in closer, he just cruises on the surface of the water and it's all over in a couple of secs. Doesn't help that the dog was constantly looking at the landward side of the river rather than at it, all the way up to the point that the gets taken.

Sharing is caring

A silly title, but best I could do with my brain racking how I'm going to accomplish a week of multitasking! For the first time, the Croc Bank bred the African slender snouted crocodile (M. cataphractus). In our off-exhibit display, one female took a long time to lay, gathering nest material. We collected the eggs, and since our whole population of this species (6) here are females, none of them were fertile. 2 months later, I observed another female basking near the nest frequently. We emptied the pond to clean it out, and just happening to examine the nest, when we found another clutch of eggs, right in the same nest! Both females are non-agressive towards each other, but defend the shared nest with rapid jaw-slaps followed by a charge from the water.

Last month, one of our 3 Yacare caiman (C. yacare) females laid a nest, which was again collected. No males here either. Now last night, we discovered that one of the other females laid in the same nest, an identical situation like the one with the cataphractus! Again, there is no agression between both females, and both of them defend their nest. Im going to try and get some pics up of both of these situations, crocs willing.

I'd be real interested to hear about similar situations.

The nesting dates are given below for the interested:

Mecistops cataphractus: Nest 1 18th June 2010 (Clutch size 23); Clutch mass 2342 gms
Nest 2, eggs discovered on 24th June 2010 (Clutch size 24);
Clutch mass 2106 gms

Caiman yacare: Nest 1 4th August 2010 (Clutch size 31)
Nest 2 8th August 2010 (Clutch size 24)

A croc attack, the real shite

Given that causative factors in attacks with reference to crocodylian behavior are seldom noted from the wild, observations in captivity can provide us much information on this information deficient aspect of behavior. Principal in this instance is Cott’s remark on studying wild crocodylian populations: “they always seem to be observing us right back”. While keeping this in mind, let us remember that attacks in captivity represent an intricate relationship between the crocodile and the target of aggression (the human in this case), rather than the passive observation of behavior, from say, behind a hide. Therefore, as an attack victim we are prey in a predator-prey relationship, rather than an observer looking from the outside. Most attacks on humans by crocs in captivity are reported in popular news-papers, e-news sites, and by the television media.


I propose that there are three instances when crocodilians in captivity may display aggression towards humans: (a) feeding response, (b) as a function of parental care, (c) a territorial response, and (d) human mistake during capture/restraint.




Well, I guess its that time, to face (a).... Time to go back in time, to March 30, 1998, 1500 hrs. The real story of a croc attack, which I've held back posting on because its so freakin embarassing. I was calling out our 16 foot mascot, "Jaws", a saltwater crocodile male believed to be originally from Sarawak. I had managed to get him half way up the sand bank, a 30 degree slope, with lots of leaves and slippery matter. In the mean-time, a keeper was getting his 4-5 kilograms of feed. I noticed the keeper come in, which distracted me for about 2 seconds, which is when Jaws made his move. I saw the lunge out of the corner of my eye and put up my right hand to protect myself....too late. He got my hand, not as hard as he could have, hardly, and having not been able to detactch it from me, he slowly started to back into the water.

I was knee deep, and keeping a close eye on his eyes, to be able to tell when he would perform the final act; no images of my life going through my mind, no remorse for the things I had'nt done, just the eye contact. I suddenly realized a blur of red on my right, and there was Ramesh, the keeper, and he strongly nudged Jaws in the neck, after which the croc opened his mouth for me to get free, and focused his attention on Ramesh. I immediately got out, and washed out the hand in a bucket of water, at which point I could see the bottom of the bucket through my hand. The rest is stupid delays in medical care, which I needed immediately, so I'll leave that part out. Needless to say I was'nt able to write legibly for around 4 months.

Needless to say, I've seen other young lads in zoos in India and elsewhere performing similar shows, take care guys!

A tale of a siamese croc and a camera trap

Camera traps. An ideal way to observe animals, in this case interactions between parent siamese crocodiles and juveniles living among them. Many know that most activity in crocs occurs at night, and a camera trip with a night vision hookup was the ideal way to observe these fascinating interactions. So, we climbed into the pen, set up the trap directly opposite where the female nests every year, under a rain tree. This was at ca. 5:30 p.m. Our head keeper, Ganga, observed the trap intact and attached to the tree at 8:00 a.m. the next day, but when I went to check at 11:00 am it was gone! Now this was ridiculous! A little investigation revealed the trap at the bottom of the pond. We fished it out with some trouble, and of course the entire unit was fried, save for the CF card, which showed images of us setting up the trap, not so useful! This is clearly a case of "neotism", the male had to have reached ca. 5 feet to remove the trap from where it was tethered, and would have actually had to brace himself against the tree to get to it. Next time I'm just going to use infra red lights and stay up at night.

The picture on the left shows the juveniles huddled with the female during a pen cleaning, this routinely happens with much vocalization between juveniles. At right is collection of the nest this year, great fun!!!