So what do I actually study?
Since I’m trying to milk this for all its worth, let’s just start with my study organism: kangaroo rats!
Specifically I study banner-tailed kangaroo rats, Dipodomys spectabilis. They’re nocturnal rodents that live in the Southwestern US and Mexico. Their entire diet consists solely of seeds – they don’t even drink water. They’ve adapted to the desert life by being extremely efficient at conserving water. For example, their urine (when they rarely pee) is 24% salt – ours is 6%. How do they do it? Simply put, the path from their lungs to the outside air is long enough that the water vapor cools and condenses before it escapes the body – and they sniff it back up. This allows them to only lose 5% of the water we’d lose in respiration.
Oh, and they’re adorable:
That silver thing you see on it’s ear isn’t a staple of kangaroo rat fashion – they’re ear tags. Each contains a unique number, and we use them to keep track of each individual. We trap them during the summer and we’re able to tell if they’ve changed homes since last year, who they’re living with, how much they’ve grown, etc. We also take small ear snips so we have tissue to do DNA testing with. There’s really an endless about of studies we can do using this data, but so far most of the work has focuses on dispersal, inbreeding, and paternity.
Did I mention they were adorable?
Their main predators are coyotes (rarely), owls/hawks (commonly), and rattle snakes (frequently). I just because I was lucky to get the photo, here’s one in action (the krat was less lucky):
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Agh. That is absurdly cute.And now I’m off for dinner. Whoo.
Is this one of the first large studies on kangaroo rats? It must be, because you don’t really hear too much about them.And that action photo of the rattlesnake is badass.
those are cute.
This is actually part 4, FYI.
That didn’t bore me. It just confused me. I have done lots and lots of reading on biology…I was just never very good at it. Wow, Jen, you’re damn smarter than I am in this field. I think I get it….but wow.
The ability to count is the first to go. Thanks, UWC.Sorry if I didn’t do a good enough job explaining it, Veritas =\ It probably would have been clearer if I had more than a half hour. Have any specific questions?
Huh. Okay, I have to admit to being no great shake at biology, but how do you determine the rate of mutation of different genes in order to find these differences? Is it an average or a trend or something? Does the rate of mutation of a specific gene just pop out naturally from sufficiently large quantities of data?Sorry, I’m in physics… so my basis for comparison is radioactive decay, which is all based on probability and all works out when you deal with big enough quantities, so that’s how I’m interpreting what you’re saying on this. I’d just like to know whether that’s what is really going on.(btw… isn’t this part 4 of this series?)
Nope, Jen. It’s clear. It just takes me 3-4 read-throughs. I have a mind that works well in a thick dusty history book. Chromosomes and I need extra time to get along.
Is this sort of like the salamanders in Central Valley of California? I know the cases are different, because that case dealt with ring species and this one is just separated populations (so far), but would I be right in saying that in time, you could end up with distinct species/varieties at each end of the valley, with transitional varieties along the length of the valley?
Ian: Mutation rates are figured out by a lot of data and math and modeling that I do not fully understand. Aka, I look it up in a paper that already has it figured out. If you want to learn more you can try here though:http://en.wikipedia.org/wiki/M…UWC: You’re very correct. Consider this project a smaller version of ring species. Since they’re not as far apart as the Salamanders you’re talking about, it’s incredibly less likely that the krats at the tips would be different species – but it’s a good analogy.The krats also have only been in this valley for the last 10,000 years or so (the end of the pleistocene made suitable krat habitat), so they haven’t had enough time to make different species yet. Maybe if you checked back a long time from now, you’d see a ring species effect.
Actually, this sounds pretty frickin’ awesome. And reminds me of that ant supercolony thing, only smaller.(Yay, finally back! I was unaware “Let’s go have dinner!” meant “Why don’t you come to the store with me to keep me company, too!” Heinlein was right.)
Now my head has asploded.
… Rodent train?I’m not going to continue this line of thought either. My brain goes for this sort of thing far too easily.
I’ll make a note in my diary…
NSFW Rodent shenanigans.
I’m pretty sure human urine is much closer to .6% m/m salt, not anywhere near 6%. You’re withholding a whole order of magnitude’s credit from the kangaroo rats!And they are adorable. Particularly compared to the snake.
If the snake ate a krat with a tag, what would happen to the tag.. (Just realized I can’t imagine snake-poop.)