According to Sophos, "in April, the switchboard of Dublin Zoo was swamped after at least 5,000 people were spammed an SMS text message to their mobile phones telling them to ring a number urgently and ask for a fictitious person. The number was that of the main phone line to Dublin Zoo and the fake names all animal-related (Rory Lion, Anna Conda, C Lion or G Raffe according to the news reports). Curiously, zoos in Houston and Brownsville, Texas suffered from similar attacks in May."
The texts will have the number they're sent from; but how hard is it acquire a SIM with fake ID - or indeed, just steal a phone and use the SIM from that?
But really: Rory Lion?!