Two slugs mean business. As we all know from watching David Attenborough, slugs are hermaphrodites. The trails on the glass, sides and even top of the terrarium, this morning give a clue that there might have been some elaborate mating dance going on last night–and some actually mating.
If these two did mate, there may be a clutch of up to 30 eggs and then…a new terrarium will be in order.
To see mating slugs check this out. Its not Attenborough, but its pretty amazing. I know we all feel sorry for the third slug.
To learn about weird slug behavior check out this Slate article on slugs.