:: GNoR BIG - New Bat Species Discovered in South Africa!" ::

 

 

 

New Bat Species identified in South Africa! October 2004 (Pictures Below)

GNoR BIG  has another contribution to Batting in South Africa!

It is showing that with the degrees of experience that GNoR BIG members are getting in the field, that there are now some useful contributions coming forward with the amount of information they are able to produce for the further and better understanding of Bats in South Africa. 

We have previously publicised that Lientjie Cohen and Koos de Wet, both GNoR BIG members and officers with the Mapumalanga Parks Board, have encountered two new cave or mine adit colonies of the very scarce species of Short-eared Trident Bat, Cloeotis percivali, with one of these finds occurring in April 2004 during a very successful GNoR BIG weekend outing in the Machadodorp area when other GNoR BIG members were also involved. But it must also be acknowledged that a previously known colony of this same species could not recently be found in an old mine adit in the Malelane/Jeppes Reef area. But monitoring of known old and new sites will continue.

We have also had greater success as a group in identifying some of the very similar and difficult species that are almost impossible to identify in the field.

Then on Monday 25th October 2004 we had a major breakthrough in the positive finding of a species of Bat that had never been located before in South Africa. In fact, it is a very poorly known species throughout it’s distribution range almost throughout sub Saharan Africa. So the species is only recorded from isolated spots, with nine known records from nine different countries. These separate records are from Senegal, Ghana, Nigeria, Sudan, eastern Congo, Malawi, Zimbabwe, Mozambique and now South Africa. But in some of those discoveries more than a single bat of the species was encountered but only at single localities.

But this small amount of experience with this species means that zoologists know very little about this species. There isn’t any knowledge, for example on their colony size, feeding manner and diet, about their roosting behaviour and their breeding biology. So now we hope that from this new finding in this country, that we can gather a lot more information about these bats and to some extent this has already started.

But the whole story started on 12th October 2004 when I was doing some work in the Komatipoort area in preparation for a documentary on a breeding colony of Sundevall’s Leaf-nosed Bats. In a moment of spare time I was checking on some bat houses that I had previously supplied to a time-share resort. I was concerned that while these bat houses had been occupied by well-established colonies of Angolan Free-tailed Bats, Mops condylurus, it now seemed that these bats may have left these Bat Houses. So when checking in one Bat House I could only find a single Yellow House Bat tucked in high up between the crevices within the bat house.

And then I went to check another of the same type of bat house, and when I opened the bottom cleaning door, I saw the rapid shuffling away and up into the crevices of several Yellow House Bats that just looked very unusual to me as they seemed larger than usual. But I did not have any reference literature with me and it was frustrating to not be able to search for some explanation on what I had just seen. I was aware, though, from memory, that there was another larger species of Yellow House Bat, but I would have to wait until I returned to Gauteng to consult the literature.

My first check was in Dr Peter Taylor’s book, Bats of Southern Africa. There I could find just two paragraphs on the bat that I suspected it to be. Then I consulted Dr Reay Smither’s, The Mammals of the Southern African Subregion. And here I found a little more information with a map showing the limited amount of findings of this bat and virtually no information on the bat’s biology and habits, but enough on the size and weight of the species to increase my belief that something very interesting had been seen in the bat house.

At the back of my mind, has been that some four to five years ago, Dr Brian Whiting and I, who have put in many hours working with and studying the bats at Ngwenya together, had on two occasions sighted single much larger insect eating bats that had exited from a bat house, but we were never able to find out what we had seen. Were we about to get to the moment of unravelling this puzzle?  

I debated in my mind the best way to check out my hunch. I concluded that it would be essential to have some companions with me who were active Bat Workers with good knowledge to help out. I contacted Lientjie Cohen and Koos de Wet, who regularly work with us on bat outings and who do a lot of bat work within their department duties. We agreed to meet at Ngwenya Lodge, near Komatipoort, in the late afternoon of Monday 25th October.

We first checked the bat house where the one Yellow House Bat had been seen on my previous visit. To my surprise this bat house was again occupied with a colony of Angolan Free-tailed Bats – perhaps 150 of them. Then we went to the bat house where we hoped to find out what type of Yellow House Bats had caused me such confusion the last time I was there.

With Lientjie, Koos and me were my wife, Rose, who was also our photographer, and Adam Palmer, who was again kindly helping us with ladders and other logistics. Koos looked up at the bat house and noticed that a large lizard was in the bat house with it’s head sticking out. This dampened our spirits, as we were worried that something unexpected may be interfering with our hopes to make a strange finding.

However, we erected our mist nets as we had intended and were happy that the weather conditions were very favourable. We were ready by 18.00hrs (6pm) and settled in for a wait. The large lizard had retreated out of sight into the bat house. At about 18.20hrs many Angolan Free-tailed Bats were overhead commencing their evening foraging on a variety of agricultural pest moths and beetles. We noticed two much larger bats than usual fly over the bat house – we were sure these were not Fruit Bats - and a few minutes later another flew over in the cross direction. But still there was no sign of bats from the bat house that we watched so intently. 

Then suddenly at about 18.45 hrs – about 25 minutes after the emergence of the Angolan Free-tailed Bat from other bat houses, there was a sudden thump into the upper mist net and we were confident that we indeed had something unusual on account of size alone. I rushed to remove the bat from the mist net in case it might free itself. With the light available from our torches I could see that it was a Yellow House Bat and that this would not be the normal Yellow House Bat on account of the much greater size. We had, indeed, captured the first Giant Yellow House Bat, Scotophilus nigrita, for South Africa. In fact, over the next ten minutes we caught four out of a colony of five, with the fifth escaping while I was trying to remove one of the earlier captives.

I could quickly tell that they were powerful creatures from the strength in their wings. They also needed to be respected, as would most other mammals of that size, as they indubitably had strong jaws and a good set of teeth in line with all species of Yellow House Bats.

As we were very aware of the need for every bit of information from this species we collected all the bat scats (guano) from the bat house. We removed our mist nets and proceeded to somewhere (the laundry) where we could have good lighting by which to do the examining and recording that needed to be done. We found that we had captured one male and three females, which seemed to make sense for the genus that is normally in colonies composed of a small harem. We measured one forearm of each bat, weighed them and examined their colouring, their teeth and the tragus – the small piece of skin that stands up in the outer ear passage – something that can help to identify species of bats. And very importantly we took a very small biopsy from the wing membrane of each bat and collected about five flightless flies for identification. No other external parasites were noticed. (It is important to note that from all bat parasite research studies, that it has been found that all external parasites that bats may have are exclusively bat parasites that evolved with them and do not go to other creatures – not even humans.)

So without any difficulties in identifying the species because of the great size (relatively) we now needed to release all but one, which we would need to submit to the Transvaal Museum for a scientific record. This is one of the unenviable tasks that go along with the job. I had hoped that there would be two males and that we could take one, but in this case we could not take the only male. Therefore one female would have to be selected. So as we released three we tried to get some idea of their echolocation frequency with the less sophisticated bat detector that we had. This meant that we could not make any recordings of their echolocation. And this also meant that the female that we would keep for scientific purposes would additionally have to help us get echolocation records from a hand held bat when back in Gauteng. 

For the record the average forearm length of the four captured bats was about 79.76mm and their average weight (mass) with empty stomachs prior to evening feeding was 84.95gms (about three times the weight of the standard Yellow House Bat, Scotophilus dinganii) while considering that the three females were probably in about mid pregnancy. These figures reveal that this species is the second largest insectivorous bat in South Africa with the Commerson’s Leaf-nosed Bat, Hipposideros commersoni, being somewhat larger.

Lientjie, Koos and I continued with some other bat work over the next two days and were rewarded with the finding of a totally albino Temminck’s Hairy Bat, Myotis tricolor, from within a colony roosting in an old mine adit.

Rose and I returned to Gauteng with the one female Giant Yellow House Bat. She became a bit of a celebrity over the next three weeks as keen members wished to view the bat, take photographs and try to get some echolocation records. The Bat, called ‘Girlie’ over that period, performed wonderfully by impressing visitors with her rugged ability to decimate the biggest and hardest beetles available. For the 3 to 3.5gm rhino beetles and similar sized scarabs, she would ambush them in her cage with rapid powerful chomps with her well developed mouthful of incisors and molars. With these large beetles she would seize the prey in her teeth, then hang up by her thumbs on the cage mesh and devour the beetle with noisy chewing within the chamber formed by her interfemoral membrane.  She was able to consume five standard size chafer beetles every thirty seconds.

She proved to be a voracious feeder on stink bugs, twig wilters, chafer beetles (ie rose or Christmas beetles), long horn beetles, cicadas, katydids, mole crickets and dung beetles of various species, and those dreadful smelly yellow and black beetles that eat flowers and soft fruit like peaches. In fact, she was a very thorough entomologist, as she knew her diet items well as ground living beetles such a toktokkie beetles were not part of the diet. She did not find any type of moth acceptable and one mantid was partly chewed before being spat out.

But for Girlie, it was not just a matter of eating as much as she could. She also had a number of engagements to fulfil; she had to attend a Committee Meeting and meet the members, she had an appointment with a visiting Bat Zoologist from Cape Town, who needed an extra biopsy from the wing for DNA information to go towards a Phd and to trace the wing shape to assess manner of flight, and she was to visit the Taxonomist at the Transvaal Museum for an acquaintance, but she was not destined to remain there. (To the inexperienced eye I believe from the wing shape that this is a very fast flying bat).

On 15th November I returned to Komatipoort for some bat related work and Girlie returned with me. It was fortunate that Dr Peter Taylor (author of the Southern African Bat Book) was able to be in the area the following day. When time allowed we erected mist nets at both the previously known bat houses that had contained the Giant Yellow House Bats. We caught a single bat of the species at each bat house, and while the one at the main colony bat house escaped while we were trying to save echolocation calls that were recorded, we did remove the other successfully from the net. This bat proved to be a male, which was a different male from the one first caught. On the strength of having this new male, I determined that Girlie should be released back into her territory.    

In typical manner Girlie devoured a full meal of scarab and dung beetles on the evening of 17th November, and then I returned her into the bat house from which she had been captured 22 days earlier. We were always conscious that we did not want to take a female bat that was likely to be pregnant at that time of the year as a scientific voucher for museum records. By the time that Girlie was released, there was every indication that she was indeed well pregnant.

But by having now supplied the Transvaal Museum with a specimen of the species of the Giant Yellow House Bat, there is now no necessity for another of this species to be collected from that same region.

There will be a research follow-up on this newfound colony of very scarce bats in the Komatipoort area, which has one of the greatest concentrations and diversities of bats within South Africa, thanks to the favourable climate and fertile feeding conditions that prevail for them.

I would like to thank all those mentioned above, who kindly and enthusiastically made such a good group enabling us to conduct this interesting work.

Nigel Fernsby.
30th November 2004. 

Images: Scotophilus nigrita

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Giant Yellow House Bat Discover & Research Team

Pictures courtesy: Mike Buchanan Left to Right: Koos de Wet, Lientjie Cohen, Nigel Fernsby, Rose Fernsby and Adam Palmer
Copyright: GNoR BIG.