Is 'in' optional?

I would write:

"Blue whales migrate to warmer areas because the water where they are is cold in winter".

I think that the "in" is not awkward and should not be inserted.

I also think that "less cold" is a strange phrase.

Re: Is 'in' optional?


Yes, I would rephrase that question. First, I would not use "less cold" - I would use "warmer". I would also not use "where they are (in)"...

I would say:

In winter, blue whales migrate to warmer areas to escape the colder waters (optional: where they were).

It seems obvious that they're migrating from "where they were", so is it really necessary to say that? Perhaps. It's up to you.

Mame said what I was going to say: we would write "waters" here instead of "water".

Don't ask me why, but we would.

Re: Is 'in' optional?
Either

Blue whales migrate to less cold areas because the water where they are is cold in winter.

Or

Blue whales migrate to less cold areas because the water they are in is cold in winter.

What do you mean "we", white man? Not all of "us" would. "Waters" refer somewhat poetically to sea areas - "I sailed north of Spizbergen, and was surprised to see a dolphin, rare in these waters" or masses of water - "Moses said some magic mumbo jumbo and the waters parted".

The environment in which whales live is a liquid called "water".

Whales migrate to warmer waters in the winter.

Whales migrate in the winter to areas of the sea where the water is warmer.

I respectfully disagree, Kemo Sabay.

"Waters" commonly refers to a large area of sea and is not exclusively poetic in use.

And, this having just occurred to me, in discussing temperature we (or I, if you prefer) would normally write "sea temperature/s" and not "water temperature" or "the temperature of the water".

It's more general, less particular, and better imho.

Hi fellow members

Thanks for the response.

Regarding 'waters', I'd refer to water in the oceans and seas as waters, whereas the water we drink, which comes from the tap, would be called 'water'. Similarly, 'rains' refers to monsoon rains. For rain which comes occasionally, I'd refer to it as 'rain'.

Am I talking sensibly?

Very.

Re: Is 'in' optional?


"because the water where they are" and "because the water they are in" are so risible perhaps they are in too deep and yet barely treading water?

Many thanks for your response.