Sandcrawler

The Sandcrawler split from its ancestor the Eardigger. It's still a scavenger, but it has developed a hard tail tip, like a sting, filled with a strong venom, so it also can attack animals bigger than it and eat them when they die. It usually bury itself into the sand, leaving its tail and its big breathing tube out. When it detects something near it, it will quickly sting it and run away under the sand using its four legs and its two ears. When the attacked animal dies, the Sandcrawler can eat it safely. Sandcrawlers have developed a curious mating ritual. During the mating season, male Sandcrawlers shake their ears (like Eardiggers did before to remove sands from their ears) as fast as they can to make a lot of noise. The female Sandcrawlers will choose the males that can make more noise. The strongest male is usually the one with the stronger muscles in the head and ears, so this ritual also have an evolutionary purpose.