Animals arrived before empty lorries (6)
I believe the answer is:
camels
'animals' is the definition.
The answer is an example.
'arrived before empty lorries' is the wordplay.
'arrived' becomes 'came' (come can mean to appear or arrive).
'before' means one lot of letters go next to another.
'empty' suggests removing the centre.
'lorries' with its centre taken out is 'ls'.
'came'+'ls'='CAMELS'
(Other definitions for camels that I've seen before include "Dromedaries" , "Mammals of desert areas" , "Animals known as ships of the desert" , "Old planes" , "Arabs call them ships of the desert" .)