New Bat Species identified in South
Africa! (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.
