According to Dictionary.com, "a hired hand who tends cattle and performs other duties on horseback". So basically someone who does all that cowboy stuff on a ranch with cows. See also Western.
The new guy everyone makes go on Starbucks runs.
Job held by Batman, Deputy Dog, Sherlock Holmes, Encyclopedia Brown, T.J. Hooker, and others.
Kind sir, might you lend a hand and add a funny job?
Someone who studies frogs (and reptiles and other amphibians). See also Science.
"Hey, uhh, wanna buy an anvil?"