Adventures in Ethics and Science

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Last weekend the weather got sunny and warm here, so the Free-Ride parental units decided it was appropriate to lead the Free-Ride offspring on a forced march along the creek.

Somehow, the sprogs didn’t get the memo that it was a forced march, since in the course of 2.5 hours neither of them complained at all. (What fun is that?)

Maybe they were distracted from their oppression by all the critters.


For the first half of our walk, the critters were mostly avian. The elder Free-Ride offspring kept a running tally of the Canada geese. We also saw a goodly number of mallards, coots, and airborne turkey vultures. We also saw a couple of great blue herons and a red tailed hawk that seemed to be looking for a small mammal upon which to sup.

Younger offspring: I am not a small mammal!

Elder offspring: What, are you a small amphibian?

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When we had gotten a good distance up the creek, we decided to take a footbridge to the other bank for our walk back toward home. This other bank had a good number of large rocks between the creek bed and the trail.

And those trails were teeming with lizards!

Elder offspring: Look, there’s another one!

Younger offspring: Aw, it just ran away!

Dr. Free-Ride: It doesn’t have time to figure out whether you’re the kind of critter who would eat a lizard.

Dr. Free-Ride’s better half: Hey, there’s a big one.

Elder offspring: There’s another one on that rock out there.

Younger offspring: (whispering) There’s a really tiny one on that close rock. It’s so cute.

Dr. Free-Ride: It is cute. I think its tail is kind of short proportional to the rest of its body. I wonder if that’s because it’s young, or whether it recently abandoned its tail to get away from a predator.

Dr. Free-Ride’s better half: Hey, there are some lizards doing push-ups!

Elder offspring: Cool!

Younger offspring: Why do they do that?

Dr. Free-Ride: I’m pretty sure it’s not to exercise.

Dr. Free-Ride’s better half: Parallax.

Elder offspring: Huh?

Dr. Free-Ride’s better half: I think it’s to help them judge distances better. Their eyes are on the sides of their head, so they don’t have the same kind of stereoscopic vision we do. But if they look at the same object from two different heights, I think they can put together the information they need about how far away that object is.

[This theory seems to have at least some support in the literature; this article mentions that lizard push-ups may “enhance distance perception by use of parallax”.]

Elder offspring: Wow.

Dr. Free-Ride: See, and I would have guessed they were just showing off and trying to look tough.

[This theory also appears to have some support; see here.]

Younger offspring: I don’t think we saw any lizards on the other side of the creek, but there are lots and lots of lizards on this side.

Dr. Free-Ride: Any guesses about why that might be?

Elder offspring: Right now this is the sunny side of the creek. It’s a good place to warm up.

Younger offspring: Oh. Lizards are cold-blooded, so they need to get their warmth from the sun.

Dr. Free-Ride: Well, they seem to have found a lovely set of hot rocks for warming up.

* * * * *
Having the forced march as our primary goal, we totally forgot to bring a camera. Younger offspring offers a view through a hypothetical camera. I don’t recall actually seeing any lizards with books, or in wedding dresses, but there were a lot of lizards out there.

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Elder offspring explores the possibility that not all of those lizards were doing push-ups willingly. I’ll note that I don’t remember seeing any snakes, but perhaps I just didn’t notice them,

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Comments

  1. #1 Wendy
    March 9, 2008

    I’d been wondering about those lizard push-ups myself – thanks for sharing those theories.

    I adore the artwork. I suspect your offspring would get on very well with mine – he has a very similar outlook on the natural world (especially the drawing with the snakes). :)

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