"Το δελφίνι και η φάλαινα είναι θηλαστικά."

Translation: The dolphin and the whale are mammals.

[Nicole966706]

An example of what language teachers call : un faux-ami: In Greek, η φάλαινα is a whale. In French, un phalène is a moth.

[Howard]

But French for "whale" is "baleine," which is likely cognate with "η φάλαινα."

[Niko837328]

It is most definitely cognates with φάλαινα! :)

[jaye16]

Right we say "false friend" and they can cause havoc in language learning. Even experienced learns sometimes slip up.

[dimitri_anto]

It seems to me that it is more natural in English to translate as: Dolphins and whales are mammals. When we refer generally to species, we usually keep it singular in Greek, but plural in English.