Arlen Specter
No. They are very territorial and VERY dangerous but not poisonous.
A snake
The adder is the only poisonous British snake, and is a reptile.
A slow loris is the only poisonous mammal in the world.
platypus!!
The only mammal that can sting is the Platypus. Male platypuses have spurs on their back ankles with from which they can inject poisonous DLPs (defensin-like proteins). Female platypuses and echidnas also have these back ankle spurs, but only male platypuses can use them.
No, an adder is not a mammal. Adders are venomous snakes found in Europe and Asia.
No, Brown Widow Spiders do not live in Pennsylvania.
No, because the platypus is not a marsupial. A platypus is a monotreme (egg-laying mammal). It is not the only venomous mammal. "Venomous" is the correct term, rather than "poisonous", as things which are poisonous must be ingested, i.e. eaten or drunk. Other venomous marsupials include the Cuban solenodon, Eurasian Water Shrew, Northern Short-tailed Shrew and Southern Short-tailed Shrew, just to name a few.
Primate
A bat is the only flying mammal.
no its not poisonous, it only bites