Re: Animal Planet's "Dragons"

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Date: Mon, 28 Mar 2005 20:29:12 -0500 (EST)

"phy" <phy00x@yahoo.com> wrote in message
news:d26lqc$6eh$1@darwin.ediacara.org...
> [moderator's note: Please note that sci.bio.evolution is a
> moderated newsgroup; this post is well on-topic so I'll let
> it go, but any discussion of creation/evolution controversies
> is banned. Stray off topic and you'll be booted. - JAH]
> "Jeff Goslin" <autockr@comcast.net> wrote in
> news:A-OdnZpd6r4H2tjfRVn-1Q@comcast.com:
> > "Rupert Boleyn" <rboleyn@paradise.net.nz> wrote in message
> > news:mbg941d1uo45bta7mpogd5t4bivtqsobd8@4ax.com...
> >> On Fri, 25 Mar 2005 19:15:34 -0500, "Jeff Goslin"
> >> <autockr@comcast.net> carved upon a tablet of ether:
> >>
> >> > No, but a cat catching a fish would be akin to aliens nabbing
> >> > humans with a transport beam from outer space, at least from
> >> > the fish's perspective. "what the... whut happened?" Yes, it's
> >> >"predatory" to do such things, but it's hardly sporting. ;)
> >>
> >> What on Earth makes you think predators are 'sporting'? Most
> >> go to lengths to avoid giving their prey a sporting chance, just
> >> as many prey animals try to avoid giving the predator a
> >> sporting chance at them.
> >
> > How did I know that was coming? ;)
> >
> > I'm just noting that if it's TOO easy to kill your prey, odds are good
> > they'll evolve a defense against it, or die out, right? There's an
> > equilibrium that gets reached, and the equation tends to work out
> > in such a way that the more difficult your prey is to kill, the better
> > it is (nutritionally) for you to eat. If it weren't nutritionally good
> > enough to eat, you wouldn't waste your time chasing it(if it were
> > hard to catch), and if it was REALLY good for you, but easy to
> > catch, the predators would survive like fatcats until they killed
> > all the prey, right? Nature has a way of working out like that.
>
> I just wanted to cross-post this to sci.bio.evolution so you
> people could get a lesson in how it *really* works. -phy

I wish that this post had a bit more context around it (What, for instance,
does the initial "No" relate to?) Also, from what group did this thread
originate?

My take on what's above - as a non-scientist - is that some is right and
some is not. I'll concentrate on the large paragraph near the end. The
statement around "if it's TOO easy to kill your prey..." seems right on to
me, but not the next part on nutrition - specifically: "the equation tends
to work out in such a way that the more difficult your prey is to kill, the
better it is (nutritionally) for you to eat." Predator/prey relationships
are more complicated than that (even with the "tends"), but the emphasis
realistically is more around ease and opportunity than it is around
nutrition. (While obviously nutrition is the whole point of any
predator/prey relationship, it's not a major deciding factor in who goes
after what.)

Take lions, for instance. They'll take down zebras, wildebeeste, kudu,
gazelles, cape buffalo and more. While taking down a cape buffalo is likely
more difficult than taking down 8 wildebeest, the 8 wildebeeste are better
for the pride in a number of ways (nutritionally, the total amount of food
is more, the ability to space out the eating over time is advantageous, the
reduced danger of widebeest over buffalo as prey, etc.)

Of course, from a purely "meat" perspective (pound for pound), I assume that
all are roughly equally nutritious, but what lions choose to go for largely
depends on *ease and opportunity*. I've seen lions go straight past zebras
and nail wildebeest, not (I don't think) because the wildebeest has any
greater nutritional value, but because there were so many of them that there
was a better opportunity in more easily splitting a huge wildebeest herd to
single out the unlucky victim than running down a smaller number of zebras.
There was surprizing efficiency displayed against wildebeest - one lioness
had a three or four minute fast jog which developed into a perhaps 10 second
sprint to nail its prey. (Had the wildbeeste not exhibited such blatant
herd mentality, they could have made it far, far harder for the lion.) When
I've seen lions get zebras, there was no large wildbeest herd around.

The upshot of all this is that even if there there could be a case made for
any relationship around how difficult your prey is to kill and how
nutritioius it is, this is not, IMO, of any real importance.

(The second last sentence in the same paragraph is a bit of a red herring in
most normal contexts, I think: predators will try to run anything down if
they're hungry enough; and the fatcats killing off all the prey is pretty
rare, unless the predator is human, or we're talking about unusual cases
like when the Isthmus of Panama was created to allow N. American predators
into S. America.)

• Previous message: John Edser: "Re: Hamilton's Rule In The Mirror"
• Maybe in reply to: phy: "Re: Animal Planet's "Dragons""
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