Power feeding

[Fuscus]

five tonnes in four years - thats a lot of fuzzies
http://www.cnn.com/2004/TECH/science/08/11/science.dinosaurs.reut/index.html

 

[Guest]

god they were BIG

 

[instar]

What an excellent story Fuscus, right up my alley, I really enjoyed this one. Wow, isnt nature awesome!! wonder what that equates to feed wise? couple of cows (weight) equivalent in smaller dinos per week? Had to be warm blooded (endo) to digest that much feed surely? cool stuff mate, keep em coming please.

 

[Nome]

Had to be warm blooded (endo) to digest that much feed surely? cool stuff mate, keep em coming please.

Good point Inny.

Thanks for that Fuscus, just been showing my home-schooled son about it, he's really into T-rex's atm.

 

[Fuscus]

The endothermic debate on dinosaurs is still not settled though the growth rate does indicate that as does other evidence. With an animal the size of an adult T.rex, temperature regulation would have been more towards keeping cool, the climate at the time was warmer than it is now but a super continent would have had cooler nights. Just its shear size would have allowed the dinosaur to stay warm during the night.
Interestingly, baby T.rex were very small, if they were endothermic then heat loss would have been a major problem. It is possible that baby T.rex had an insulation type covering , maybe even feathers. :shock:

 

[Nome]

.... It is possible that baby T.rex had an insulation type covering , maybe even feathers. :shock:

I can just picture a little t-rex chicky running around

 

[instar]

Is it possible they were capable of metabolic change as they grew? ecto as juvies, slowly becoming more endo as adults?? its an intresting debate ive been following for a while.

life finds a way eh!

 

[Sdaji]

When we were studying paleontology last year we went through the arguements for dinosaur endothermy, and it was virtually all a load of garbage. The only vaguely convincing piece of evidence was the bone structure, which seemed to resemble extant endothermic animals' bone structure, but even that wasn't too convincing because what you're looking at is a rock which is in the shape of a bone which hasn't existed for millions of years.

This article is saying they're looking at the growth rings!!! GROWTH RINGS OCCUR ON COLD BLOODED ANIMALS! They don't appear on endothermic homeotherms!!!

(someone correct me if I'm wrong!)

There are lots of large cold blooded predators, eg crocodiles, sharks (yes, I know some are semi homeothermic/semi endothermic, but they still have lower temperatures that goannas etc, so the 'they'd have to be endothermic to handle that amount of food' argument doesn't hold.

I'm warm blooded, but I didn't grow as quickly as some of my pythons, which have managed to sustain growth rates of around 4cm per week for over a year, or put another way they've probably increased in size (mass) by a factor of 5-10 in their first year, at a very very rough guess. I had a water python grow from 32cm to 184cm in 12 months, so I don't think that being ectothermic means you'll grow slowly or be unable to process large amounts of feed.

 

[Fuscus]

A more detailed version of the article
http://www.newscientist.com/news/news.jsp?id=ns99996274

 

[instar]

They don't appear on endothermic homeotherms!!!

Are trees endothermic homeotherms Sdaji ? You wernt there either mate! :lol:
With all the incredible evolutionary adaptions that can be witnessed on the planet today, I dont find the possibilty all that unlikely (endotherms) Much science is theory, until it can be [proven. :wink:
Fascinating stuff anyway.

from the 2nd article....

It therefore achieved its gigantic size not by growing for longer, as do modern mammals and lizards, but by growing dramatically faster. An adolescent T. rex would have gained about 2 kilogrammes a day between the ages of 14 and 18, before slowing down and settling into adulthood.



Superfast metabolism dosent sound alot like en ectotherm though does Sdaji? How warm was the world 65 million years ago?

 

[Hickson]

The world was very warm and humid back then, Inny.

It is possible that, if a dinosaur ate a large bulk of food, the metabolism of that food would generate lots of energy, and maybe some of that could have been diverted back towards further metabolism - much in the same way as an alternator charges a car battery while the engine is running.

Just trying to think sideways.........

Hix

 

[instar]

Hey! thats a darn clever theory Hix, you might have something there????

 

[Sdaji]

Are trees endothermic homeotherms Sdaji ?

No, they most certainly are not, thus, it's not suprising at all that they have annual growth rings.

Growth rings occur on cold blooded animals because in winter they slow down and don't grow, not on warm blooded animals (even things like bears, which hibernate). Even on a freshly obtained skeleton from a reptile, the growth rings aren't reliable, let alone a fossilised bone (rock formed in the shape of a now non existent bone). This very, very weak evidence for dinosaur endothermy relies on something which eliminates the only half convincing piece of evidence.

 

[Fuscus]

Hix, unfortunatly it boils down to the formula calories in - calories out = weight gain. Calories in is food that can be assimulated while calories out is the amount of energy required for day to day life.
Unfortunatly this doesn't tell us anything if the animal was endothermic or not. If it was endothermic then all it means that a lot more food would have been required because there would have been higher day to day calorific requirements.