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Bat research is fascinating

my research project on sperm competition in bats

Hi folks – long time, no blog!

I have written before about the relationship between testes size and brain size in micro bats (aka echolocating, insect-eating bats as opposed to fruit or nectar eating bats). Many of you have also emailed me information about the scientific study that was published in 2006 by research team Pitnick et al. that first demonstrated this relationship. Thank you very much for that and in exchange I thought I might give you a bit of an update on what I am in the middle of doing to further our understanding of the brain-testes relationship in bats.

For my masters degree I am looking at whether or not there are any differences in the brain volume of male and female micro bats. I have been wondering if there might be ever since reading about Pitnick et al.’s study. My thinking was that if there is, indeed, some sort of inverse relationship in bats between brain size and testes size whereby the two metabolically expensive organs trade off against each other then it stands to reason that perhaps females could have larger brains than males since they don’t have testes competing with their brains for dominance in the body. At least, I thought, this might be the case in species where males have very small brains due to their enormous testes which hog all the body’s resources.

My study is fairly small in scale but I am hoping that it will still prove interesting. I am comparing averages of male and female brain volumes in 9 Australian micro bat species – some that have mating structures where females are promiscuous and some where females are loyal to a single mate (a dominant male harem leader). To do this we are CT scanning a collection of skulls and then using computer technology to create 3D models of the brains as a way to ascertain volume.

Here’s a picture of the first skull we scanned. It makes me laugh every time I look at it – such a big machine to scan such a tiny object (that little spot on the blue towel is the skull):
going through the CT scanner

And here is a model I am putting together of that same skull. It needs work but it’s still pretty cool:
model of a bat skull - in progress!

Interestingly, the factor that influences testes size in micro bats in female sexual behaviour. When females are highly promiscuous and take many sexual partners the males tend to have much larger testes than species where females are loyal to a single mate. It is assumed that the large testes trait develops in species where females are promiscuous because there is greater competition among sperm for access to the eggs in these individuals and so those males with more sperm available tend to be selected for over time. It is similar to how if you are really keen to win a meat raffle you will buy more tickets.

The same relationship between female promiscuity and testes size occurs in primates, including humans and for that matter, basically all animals. You can look at most any wild animal and get a good idea of the level of female promiscuity by looking at the testicles of the males. The difference with bats is that because bats weigh very little (as little as 2 grams!!) and have an extremely tight energy budget they cannot afford to have both heavy brains and heavy testes and so they trade one tissue type against the other.

Pitnick and his colleagues in their landmark study originally predicted that the opposite relationship would occur – ie that large brains would equal large testicles. They postulated that species with promiscuous females would have larger brains as a way for the males to avoid being cuckolded. They were surprised when they discovered that the opposite was true and remarked that “perhaps monogamy is more neurologically demanding.” I think many of us would attest to the truth of this statement!

If my study shows that there are any size differences in male and female bat brains as a function of testes size it may potentially mean that female promiscuity is a force strong enough to influence male intelligence in a measurable way. An intriguing notion but at this stage very much a theoretical one.

*Sidenote: the boys on the construction sites where I have been working have heard me talk about animal testicles so much that they have become terrified I’m going to show up at their bedroom door one day with my calipers! Actually that’s not completely true .. some have actually volunteered for the job! .. all in the name of science, right? 😉

** Oh and yes the bat in the picture above is alive! It was just very very cold because I pulled it from a tree which had just been buldozed on a construction site in the very early hours of a winter morning.

Size matters – and if it didn’t, you’d be smaller

Does size matter? It’s the age old question. Some say that it’s the ‘motion of the ocean’ that matters while others have pointed out that ‘they don’t make small dildos’. Still others have pointed out that, actually, they do make small dildos! If you ask me, I’ll tell you that size does matter. But I’m not just speaking of pers

onal preference, here. The question of whether or not length and/or girth is important becomes obvious if you look, as I always do, to the animal kingdom.

Male humans, you see, have penises far larger than any of the other primate species around the world. Even Silverback gorillas, as massive as they are, only manage to achieve erections of about 1.5 inches. Many theories have been put forward for why humans have such large dingdongs. Originally they wondered if a big penis might have evolved to make insemination easier but that didn’t make sense since the less endowed primates are just as good at breeding as we are. They then thought a big wang might be useful in male/male competition (aka showing off) but then they realized that most indigenous cultures have coverings over their genitals so that didn’t seem like a good explanation either. They then wondered if a big cock might have evolved to help us to perform some of the more adventurous kama sutra style position that many of us are quite partial to but that also didn’t make sense because orangutans, chimps, bonobos and many other primates are into all the same crazy shit that we are – and then some!

Finally someone wondered

if female choice might have been involved but this was dismissed almost immediately after a few studies showed that women don’t really like looking at penises. This isn’t surprising considering what a huge epic fail playgirl magazine was!

So if women don’t even like to look at penises could female selection really be involved in the evolution of the huge human wang? Well as Meredith Small points out in her book ‘Female Choices: Sexual behavior of female primates‘ .. and as what virtually all women already understand .. a woman doesn’t have to love the sight of a cock to appreciate how it feels. Hence it is entirely possible and indeed very likely that the reason men have such large penises is that women enjoy them so much that over time they mated more often with these big boys than with the little smokeys and essentially bred the big cock gene into the species. Women, therefore, are amazing designers. Not just of fashion and homes but of men – and their penises!

Of course female don’t’ always have choice over who they mate with. There are arranged marriages and tribal system where a dominant male type character has rights to females and of course there has always rape. Also women will also make mate choices based on things other than cock size (shocking, I know). But generally speaking it can definitely be argued (and I do) that there have been enough women choosing mates based on their cock size over the last few thousand years to increase the size of human penis beyond what would ever be necessary on a purely functional basis.

So does size matter? Of course it does .. but don’t worry. You’re already doing way better than almost any other primate on Earth.

If you enjoyed this you might also enjoy my post on primate testicles

perspectives on minimalism from remote locations in Australia (90 day consumerism detox – day 41!)

Hello everyone!!

I haven’t had a chance to keep up with this blog for a while – way too much going on! I’m doing about 80 hours a week of fauna spotting at the moment in a remote site in Central Queensland. It’s been pretty epic and there hasn’t been much time for anything else. I wanted to update you all, though, on my progress with the 90 day consumerism detox. Today is day 41 so just about half way there!

I honestly can’t believe I’m only halfway there, seems like ten years since I’ve bought anything! With my new job, it’s actually proving very easy not to buy crap because I get sent out for 4 weeks at a time to remote locations where there really aren’t any opportunities to buy stuff, anyway. The only ‘stuff’ anyone seems to buy around here is beer and cigarettes. At the end of each 4 week stint they send us home for a week but a lot of people out here (at least the ones who aren’t married) don’t even have a ‘home’ to go to. They just stay with friends or zip of to Thailand or Fiji for the week. Some of them have stuff in storage but a lot of them don’t seem to own much of anything. It’s pretty amazing and a great practical lesson on minimalism.

I’ve spoke before about the strange phenomenon that occurs when you take a break from buying crap. It seems that the less you buy, the less you want for things and that’s definately what’s been happening for me lately. For example, yesterday I went to a mall. It was crazy. Save for a few field guides and odds and ends I needed for work, I haven’t bought anything for myself in six weeks and up until yesterday, I hadn’t even seen a shop in weeks, let alone an actual mall. We were only there because there were two of us that desparately needed a new phone plan. Telstra seems to be the only phone network out here that serves the area we’re at and yesterday me and another girl got seriously lost for like three hours and were totally incommunicado from the rest of the world because neither of us had Telstra. Anyway, so me and this other girl were waiting in line at the Telstra store yesterday trying to solve our communication issue and realised that we actually had access to stuff! We found ourselves just standing there, wracking our brains about what we might want to buy but neither of us could actually come up with anything. Well, Lauren did buy some granola but that was it.

Usually, after a month of isolation you’d think you’d be desperate for stuff but we weren’t. It’s amazing what a break from consumerism does for you. It really puts life into perspective.

Is it possible to be a vegetarian and still eat the occasional cheeseburger?

I love cheeseburgers. Like. I LOVE cheeseburgers. I could easily give up chicken, pork, fish, shellfish, and virtually all other meat forms so long as once a month or so I could burry my face into the delicious, juicy, mouth-waterwatering goddess blessing that is a good cheeseburger.

But I feel guilty.

On and off from the age of 17 I have attempted to kick meat out of my life. I would do really well with it for a while but then have some kind of minor life crisis – a breakup, a job loss, backing into a guard rail, etc. – and then I’d fall off the wagon. In these times of high anxiety nothing could calm me like a Big Mac or a Dicks Double Delux could (those of you who are from Seattle know what I’m talking about).

But I really do want to be a vegetarian. Honestly, I want to be a vegan. I respect the lifestyle choice so much and I am aware that if everyone on Earth was a vegan, we would be able to easily feed all the world’s people. And that’s amazing! I am also aware of the effect of livestock on carbon emissions and of what goes on in factory farms – and of what goes on even to animals lucky enough to live on organic, free range farms when they are trucked to the slaughterhouse.

I feel like the most ginormous hypocrite in the world for the fact that I still occasionally eat meat. It’s no longer a regular thing but it still does happen. The other day, for example, I ate a venison pie. It was on a four-wheel driving course and I was the only woman there. The boys were all eating pies and so I ate a pie .. and it was delicious .. but I hate to think of what was involved in getting it to the table.

Some of my other weaknesses are oysters, sardines, and buffalo (I guess I just love weird stuff).

About two years ago I started to (yet again) begin transitioning meat out of my life. I stopped eating it at home but still allowed myself to eat it, if I wanted it, when I went out. For a long time I was happy with that. I was aware that it wasn’t ideal but at least I had lessened my consumption .. and that was (and continues to be) what I recommend for other people. I don’t tell people that they have to become perfect non-chemical, non-GMO, Vegans – it’s just great to substitute meatless, more humane, and more natural choices whenever possible.

And yet I expect more than that of myself. I don’t know if I just have higher expectations for myself than I do for the rest of the world or what, but I am finding myself with a lot of guilt for ever eating meat at all – and yet I really struggle with giving it up. Gahhh!!

What are everyone’s thoughts??

Photo credit – with thanks.

What do you really need this Christmas?

Hi everybody,

In the lead up to Christmas I have been pondering the question of “what do you really need?” The answer, of course, is very little. I love the saying that all you need is “someone to love, something to do, and something to look forward to”. I guess there are a few other things you need, as well – something to eat, something to drink, shelter from the elements, etc. – but none of us really needs very much and I suspect that everyone reading this has most, if not all, of what is really necessary in life.

I can understand as much as anyone the desire for more. I’ve recently moved to a warm climate and I have been having fun buying new dresses and summer clothes. Luckily, though, I have learned to recognise when I become enchanted with the idea of a possession that costs money, contributes to clutter, and won’t really enrich my life. Last June I made an effort to not buy a single item (aside from the necessary groceries and toiletries) for the entire month. It was a great exercise and I definitely saved money but the big take home was I realised that if I could just resist leaving an item momentarily and walk out of that part of the store, the desire for the item would leave almost instantly.

It’s easy to see how constant consumerism can drain your personal finances and make your house a cluttered nightmare but when you start thinking about it from a global perspective it starts to become really frightening. In essentially every moment of our lives we are influencing the lives of people all over the world – not to mention the world, itself! I was saying to a friend this afternoon that even if you so much as use a public toilet and wash your hands you have to wonder about who made the soap and what the working conditions where like, what was in the soap and where will it end up after it goes down the drain, how did it get here and how much carbon was released in the process, etc. When you think about everything in this way you start to realise how dangerous our culture’s incessant consumerism is – and I know I am fearful of what the future effects of it will be.

I don’t want to go all negative-town on you guys but I was just curious about if any of you keep this sort of stuff in mind when it comes to your holiday giving and receiving? A few years ago my brother gave me a Kiva gift card which was really awesome. With Kiva you loan money to people in under-developed countries for entrepreneurial endeavours. I loaned my money to this old man who wanted to buy some ladders to pick coconuts. As Kiva gives out loans, not grants, I did get the money back eventually and when I got the email saying that my loan had been repaid I was actually in a tight money sitch and so it was a super awesome moment! I’m sure it was awesome for him, too, when he got the loan and was able to buy his ladders! Lately I’ve also been giving out gift cards for movies, restaurants, etc. a fair bit. People are always stoked about them and they don’t contribute to material consumerism or clutter which is exciting to me. Gift cards are also super cheap to send (esp. if you have relatives overseas like I do) which makes it doubly awesome!