They do get a lot of water from the food they ingest, but they also have bigger kidneys that are much better at processing the salt out of salt water than our kidneys. Living in an aqueous environment they don't need as much water because they don't lose as much either. http://marinelife.about.com/od/Whales/f/Do-Whales-Drink-Seawater.htm
I denti delle balene hanno subito una modificazione, sono diventati elementi di un filtro enorme, chiamati fanoni. Attraverso i fanoni la balena filtra l'acqua, trattiene dei piccolissimi crostacei, simili a gamberetti, chiamati krill, e l'acqua viene espulsa. Questi gamberetti sono il nutrimento principale della balena. Attraverso essi assume proteine, energia (sotto forma di legami altamente energetici contenuti ad esempio nel fegato dei gamberetti o nel loro carapace) e... assume liquidi! Infatti, grazie al sistema regolatorio del gamberetti, i loro fluidi interni hanno una salinità inferiore a quella dell'acqua marina, una salinità abbastanza bassa da risultare in attivo per il trattenimento dei liquidi da parte della balena.
The whale drinks the water it's in, not just any water in general. It does not drink fresh water, for example. Therefore the article (it's also required in English).
Teaching the use of the definite article is behind the scope of Duolingo, so it's maybe better to check it on any good grammar site.
I was under the impression that it's the other way around, that in contexts like this, Italian uses or omits the definite article the opposite way that English does:
La balena beve l'acqua = The whale drinks water ~ The whale is in the habit of drinking water.
La balena beve acqua = The whale drinks the water ~ The whale drinks some particular water.
la balena beve acqua is a general statement: it's not specified which water it's drinking.
In La balena beve l'acqua, acqua was mentioned before and it's now been referred to.
The rule is the same as in English: Italian is just more find of its determinate articles and use them more extensively than English.
In Italian, using an article like this means it's a habitual practice, rather opposite to English in which the lack of an article in this context means it's a habitual practice.
La balena beve l'acqua = The whale drinks water (general habit)
La balena beve acqua = The wale is drinking water (specific instance)
Rae. F: I'm afraid it's the other way around.
La balena beve acqua is a general 'habit', with no reference to specific water.
La balena beve l'acqua is a specific instance, referring to the water mentioned before or a special water.
Another example: le mucche producono latte -> that is what they do.
Le mucche producono il latte -> the milk used in that farm, for that cheese, sold in that store.
We already had this discussion in some other forum :-)
When no article is specified in this kinf of sentences, then the partitive article (unexpressed) is actually used.
La balena beve (dell')acqua.
See here (25 & 26): http://www.treccani.it/enciclopedia/partitivo_(Enciclopedia-dell%27Italiano)/
I check what this word means, you know by putting the mouse over the underlined word and it gave me the following as a definition... Fatty, Flares, Flash? I put "the dolphin drinks water" and i got it wrong, but how was i suppose to know it it didin't give me a definition?
Through coming to the comments page, I have learned to check other resources (many great ones are offered here by fellow learners). At first I felt like it was cheating if I checked before I answered the question on duo, but I think it's best to go with whatever works best for your learning style.
Es gab nichts bess’res für den Wal als eisgekühlten Ginger Aal.
It’s a German pun, meaning: There was nothing better for the whale than ice-cooled ginger ale/eel.
Here’s a fitting illustration: http://apfelhase.de/post/176147591631/es-gab-nichts-bessres-für-den-wal-als
The salt has nothing to do with it. The blowhole is how they breathe.