The Roman Republic/Empire had a long-term foothold in Northern Africa, with provinces such as Aegyptus (Egypt), Cyrenaica (Libya), Africa Proconsularis (Tunisia, Algeria), Mauretania Caesariensis (Algeria) and Mauretania Tingitana (Morocco) all at various periods of time under direct Roman administration.

So it’s very likely that said provinces would have interacted and traded directly with Berbers, Nubians etc. that would have had direct access to the animals to which you refer. Following said exchange, it would have merely been a matter of transportation. Modern scholars, citing passages written by Pliny the Elder, suggest Roman boats could travel between Ostia (Rome’s principal port) and various locations in the provinces of Africa at a speed of about 6 knots, which would mean the journey could take anywhere between 2-8 days depending on weather conditions and the precise point of departure from Africa.

In fact, there was a whole industry centered around the capture and transportation of these exotic animals for entertainment events for the Roman populace. This article goes much more in depth than my own personal knowledge on the subject if anyone is interested.