Moles are small, subterranean mammals.

He's promising to bring evidence of a Russian mole inside Berlin Station.

Même si le Général [De Gaulle] avait autorisé une enquête, nous aurions créé une atmosphère de suspicion générale. Sans avoir la moindre chance d'identifier la taupe (...). La seule solution consistait à tenir notre information secrète et à protéger notre source. Tant que notre contre-taupe n'était pas détectée, nous restions en position de force (L'Express, 28 févr. 1981, p. 127, col. 2)

Even if General [De Gaulle] had authorized an investigation, we would have created an atmosphere of general suspicion. Without having the slightest chance of identifying the mole (...). The only solution was to keep our information secret and protect our source. As long as our counter-mole remained undetected, we remained in a position of strength

мультфильмы про маленького крота

cartoons about a tiny mole

У нас в команде крот. 

We have a spy in our team.

Bahçemde bir köstebek var.

I have a mole in my garden.

Şu an yanında bulunan ekibinde bir köstebek var.

There's a spy within your team on the train now.