Aelian, History of Animals 4.53
“Eudemos says that while the animals have no reason they do have a natural ability in arithmetic even though it is not taught. He adds as proof of this that one of those animals from Libya. He does not provide it with a name, but here are the things he says.
He claims that whatever it hunts, it separates into eleven portions and eats ten of them, leaving the eleventh. (why it does this and for whom and with what plan is worthy of examination). This is a kind of first-fruit sacrifice or tithe, you might say. Therefore, it is right to be surprised at this self-taught wisdom: for the animal without reason knows the counts of one and two and the subsequent numbers. Just compare how many lessons are required for a human being, how many punishments they need, so one might learn these things well and correctly, or, how often one does not learn.”
Εἶναι δὲ ἄλογα μὲν ζῷα, φυσικὴν δὲ ἔχειν ἀριθμητικὴν μὴ διδαχθέντα Εὔδημός φησι, καὶ ἐπάγει μαρτύριον ἐκεῖνο τῶν ἐν τῇ Λιβύῃ ζῴων. τὸ δὲ ὄνομα οὐ λέγει· ἃ δὲ λέγει, ταῦτά ἐστιν. ὅ τι ἂν θηράσῃ, ποιεῖν μοίρας ἕνδεκα, καὶ τὰς μὲν δέκα σιτεῖσθαι, τὴν δὲ ἑνδεκάτην ἀπολείπειν (ὅτῳ δὲ καὶ ἀντὶ τοῦ καὶ ἐννοίᾳ τίνι σκοπεῖν ἄξιον) ἀπαρχήν γέ τινα ἢ δεκάτην, ὡς ἂν εἴποις. οὐκοῦν ἐκπλαγῆναι δίκαιον τὴν αὐτοδίδακτον σοφίαν <τήνδε>2· τὴν γάρ τοι μονάδα καὶ δυάδα καὶ τοὺς ἑξῆς ἀριθμοὺς ζῷον οἶδεν ἄλογον· ἀνθρώπῳ δὲ δεῖ πόσων μὲν τῶν μαθημάτων, πόσων δὲ τῶν πληγῶν, ἵνα ἢ μάθῃ ταῦτα εὖ καὶ καλῶς ἢ πολλάκις μὴ μάθῃ;