Anaerobic Stamina (Was Re: [Terramegathermy in the Time of the Titans (long...)])

[archosaur@usa.net]

Finally got a hold of the ref. It is:

Seymour, R.S., Bennet, A.F., & Bradford, D.F. 1985, Blood Gas Tensions and
Acid Base Regulation in the Salt-Water Crocodile _Crocodylus porosus, At Rest
And After Exhaustive Excercise. J.Exp.Biol vol. 118 pgs 143-159


Excerpt: 

Bicarbonate PH diagrams of laboratory excercised crocodiles demonstrate the
pronounced metabolic acidosis, with plasma (HCO3-) immediately decreasing
along the CO2 isopleths (Fig 3). During the first hour of recovery, an initial
respiratory compensation is apparent in Fig 3 and is also indicated by a
rising trend in arterial PO2 and a drop in PCO2 in the face of low PH (Fig 4).
However the major adjustment was metabolic removal of lactate which was nearly
complete in four of the five animals after the 3-hr period of recovery.

__________

The tests were performed on 7 _C.porosus_ rangin from 0.43-7.0 kg. The
"excercise" was accomplished by prodding the animal's tails and legs by hand.
The result was many repeated, explosive, bursts of energy which continued for
1-2 minutes and then gradually died off until exhaustion was reached at 5
minutes.



Now that was a small animal. If we look at HP Adam Britton's Bennet
reference:

Bennett, AF, Seymour, RS, Bradford, DF and Webb, GJW (1986). Mass-dependence
of anaerobic metabolism and acid-base disturbance during activity in the
salt-water crocodile, _Crocodylus porosus_. J. exp. Biol. 118: 161-171

Regarding croc size and anaerobic ability:

Animals <1.0 kg struggled for 5 minutes till exhaustion
Animals  that were between 10-100kg took 10-20 minutes and animals that were
>100kg took 30 minutes or more before exhaustion was reached.

Indeed even after all that most of the animals had already shown partial
recovery 2 hrs later. The only acception was one individual who was still
highly acidic 4 hours into the recovery period. This croc was exceptional
though, since it excercised to the greatest amount of exhaustion and wound up
with a blood PH of 6.87 immediately after excercise (which later fell to 6.42,
the lowest blood PH for any known animal).

One final thing on croc anaerobic endurance. Bennet et al showed that lactate
elimination speed was independant of size while proton elimination actually
increased in larger animals.

Again this is intense periods of explosive movement. Not just normal movement
back and forth. Plus sauropods were many times larger than extant crocs. Now
if a 180kg croc can last 30+ minutes doing an explosive workout, imagine how
long a sauropod could go, just moving normally.

This is, of course, assuming that they had hyperanaerobiosis as a form of
movement (why?). 

Anyhoo, there's the ref, plus one ref more :)

Jura


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