Comments on: Which came first in whales: extreme breath-hold diving or large body size?

By: Gerry Palmer

Gerry Palmer — Fri, 11 May 2018 08:28:19 +0000

Could we not get a hint at the answer by looking at the cancer rates and genomes of other large animals – especially those that are not subject to the issue of holding their breath – e.g. elephants, mammoths, hippos etc.

If they benefit from reduced cancer rates (as I assume they do based on their lifespans which are broadly similar to us much smaller humans – African elephants 60 – 80 years, rhinos and hippos 40-50 years) then there is at least a small implication that the breath and cancer are not related. Which would tend to imply that holding their breath is a serendipitous following on due to the needs of the environment.

However you would obviously need to examine the genome to get a better view.

By: enrico

enrico — Tue, 13 Mar 2018 23:57:55 +0000

Thanks! Very interesting (yet light) post!

By: Jack Gray

Jack Gray — Mon, 12 Mar 2018 17:04:43 +0000

Feeding and Reproducing is all that whales do. However, there are several species in the oceans of the world, that rely on whales visiting certain sites, and therefore are an indication of how healthy our seas are. For instance, there are whales that dive down deep, to hunt, either for fish or for giant squid.
Thus, some species in the sea’s are poisoned by plastic bags, instead of thinking that they were jellyfish.

By: Lorna Seldon Burd

Lorna Seldon Burd — Wed, 26 Oct 2016 05:48:32 +0000

I am really enjoying all your articles very much ! Great humour & out of the box presentations – thanks for making this such a great course 🙂

By: Didier

Didier — Sat, 20 Feb 2016 23:51:05 +0000

What a shame that you didn’t see whales up close.The Sea World trip is usulaly really good and very convenient if you are staying in Surfers Paradise or near there. If you go again, may I suggest you try the folks down at Coolangatta Whale Watch, it is a bit of a drive, but they are a family business and they really go out of their way to make the trips special. They have had an awesome season of whale watching this year, and on about 50% of their trips they are seeing dolphin pods too. Now is the time for mothers and calves (baby whales).Sadly for Min (who commented above) April is not a time for whale watching, but there are lots of other things to do and see.CheersAnnie from Gold Coast

By: praveen kumar tiwary

praveen kumar tiwary — Sun, 20 Sep 2015 15:50:53 +0000

just like humans is there any whale are tinny at there adult age?
what is petos paradox?
how whales overcome from stress causes by hypoxia?
why whales live deeper in sea?
how they got that much ability of oygen holding capacity?
why there fertilisation time is that much short

By: Roger Forster

Roger Forster — Tue, 15 Sep 2015 10:50:07 +0000

If humans did a lot of breath hold diving would they develop a reduced incident rate of cancer? Has any study been done of Pacific people who live on the sea and dive every day for their food?

By: Marc Pradas

Marc Pradas — Mon, 10 Nov 2014 09:14:35 +0000

Very interesting article indeed. Thank you very much.

Yet I thought that hipoxia didn’t produce much oxygen reactive species as a result of precilsey the lack of oxygen. Hypoxia creates many other substances that can have toxic effects over the cells and disregulates other chemicals 8like calcium, CO2, O2, etc.) in blood with potential harmful effects.

Anyway, I’m not much in a position to discuss here. Thanks again

By: Maritza Garcia

Maritza Garcia — Mon, 10 Nov 2014 02:50:20 +0000

I think that if there were not many big predators in the sea when whales evolved the selective pressure for such a big size would not have been as strong as the pressure toward niche occupation regarding food sources so I would conclude that the capacity for extreme breath-hold diving was more beneficial towards survival and the big size was a “side effect” of adaptations against hipoxia aided by the buoyancy that water provides. But I wonder why dinosaurs got to be so big being affected by their weight. Was it predator pressure?