Recurring Guest Characters Narrator 123 guest appearances Host 14 guest appearances Narrator 12 guest appearances Narrator 7 guest appearances Narrator 6 guest appearances Host/Biologist 4 guest appearances Narrator 2 guest appearances Narrator 2 guest appearances Narrator 2 guest appearances Correspondent 2 guest appearances Narrator 2 guest appearances Host/Neuroscientist 2 guest appearances Reporter 2 guest appearances Venetia Burney 1 guest appearances Astrophysicist 1 guest appearances Presenter 1 guest appearances Narrator 1 guest appearances Narrator 1 guest appearances Narrator 1 guest appearances Narrator 1 guest appearances ⇤ « 1 2 » ⇥