A wolf pack if fast enough or in a surrounding position could easily kill a kangaroo. At full hop they could not catch it from behind. Dogs can kill a roo. Greyhounds are used to run them down. So a pack of wolves no problem Roos can kill dogs by ripping their stomachs open with their hind legs. Also can enter water and then drown a dog if it swims in after the roo, by pushing it under the water with its front legs.