After theorizing that NFL teams were the most likely in sports to be named after predatory animals, given the violent nature of football, while MLB teams were perhaps the least likely to be named after violent beasts, I’ve categorized the names of the 30 MLB teams, 32 NFL teams, 30 NBA teams, and 30 NHL teams. The lists follow, with names current as of spring 2014:
MLB: 30 teams
named after mammals: 3 (Tigers, Cubs, Royals (a commenter notes the team was originally named for Kansas City’s American Royal livestock show, not after royalty)
after reptiles: 1 (Diamondbacks)
after sea creatures: 2 (Rays, Marlins)
after people: 15 (Padres, Giants, Dodgers, Pirates, Astros, Brewers, Phillies, Mets, Braves, Nationals, Mariners, Athletics, Rangers, Indians, Yankees)
after birds: 3 (Orioles, Cardinals, Blue Jays)
after clothing: 3 (Red Sox, White Sox, Reds)
after heavenly creatures: 1 (Angels, of course)
after geography: 1 (the Rockies)
after cities: 1 (the Twins)
NFL: 32 teams
named after mammals: 8 (Rams, Panthers, Bears, Lions, Broncos, Jaguars, Colts, Bengals)
named after birds: 5 (Ravens, Cardinals, Seahawks, Falcons, Eagles)
named after sea creatures: 1 (Dolphins)
named after people: 16 (Patriots, Steelers, Browns, Texans, Titans, Raiders, Chiefs, Giants, Cowboys, Redskins, Packers, Vikings, Saints, Buccaneers, 49ers, Bills-Buffalo Bill Cody)
named after transport products: 1 (the Jets)
named after climate: 1 (the Chargers)
NBA: 30 teams
named after mammals: 4 (Bulls, Bucks, Grizzlies, Timberwolves)
after reptiles/dinosaurs: 1 (Raptors)
after climate: 3 (Heat, Suns, Thunder)
after people: 9 (Celtics, Warriors, Wizards, Cavs, Mavs, Knicks, 76ers, Trailblazers, Kings)
after geography: 1 (Lakers)
after birds: 2 (Pelicans, Hawks)
after objects: 5 (Pistons, Nuggets, Rockets, Spurs, Clippers)
after insect: 1 (Hornets)
after music: 1 (Jazz)
after basketball: 1 (Nets)
after misc.: 2 (Magic: after the Orlando theme park, and Pacers: pacing is done in harness racing and in car racing, so a Pacer is presumably the person who does the pacing)
NHL: 30 teams
named after people: 11 (Kings, Islanders, Canadiens, Rangers, Senators, Flyers, Canucks, Maple Leafs, Blackhawks, Blue Jackets, Red Wings)
mythical creature: 1 (Devils)
oil: 2 (Flames, Oilers)
birds: 2 (Penguins, Ducks-but first named after the Mighty Ducks movie )
mammals: 4 (Bruins, Panthers, Predators, Coyotes)
places: 1 (Capitals)
sea creature: 1 (Sharks)
object: 2 (Sabres, Stars)
music: 1 (Blues)
climate: 3 (Hurricanes, Lightning, Avalanche)
environment: 1 (Wild)
transport products: 1 (Jets, formerly the Thrashers)
Also, for the 31st NHL team, the Vegas Golden Knights, read this from their primary owner, Bill Foley: “The Knights are the epitome of the warrior class. They’re team-oriented, they always stick together, they never give up, they never give in. And hockey players are warriors. They’ve always been team players, all for one. That’s us. That’s what we’ll be.”
Misc. Baseball 
Get up to date. The Atlanta Thrashers moved a year ago and became the Winnipeg Jets. The Jets were named after a plane.
Magic – an amusement park: Magic Kingdom
I see the New Orleans Hornets will be renamed after another flying creature, the Pelicans, starting with the 2013-2014 season: http://www.nola.com/hornets/index.ssf/2013/01/tom_benson_makes_it_official_t.html
check out the wikipedia article on early history of STL Cardinals. They were named after the shade of red of their early uniforms, they were not named after the bird. So the Cardinals are named for a color. It’s a coincidence that there is a bird of that name as well
also see the wikipedia article on the history of the STL football Cardinals, predecessor of the Arizona Cardinals. This team was originally the Chicago Cardinals, also named after the color of their uniform.
And now the Hornets have been renamed the Pelicans, giving the NBA two bird teams and no insect teams.
The bobcats are now the hornets so there should be 4 mammals
There’s actually only 2 NFL teams named after people. Specific people.
Dolphins are also mammals.
Frank
Maple Leafs are named after the leaf of a maple tree, not people.
Jets are named after objects (or military in their modern incarnation) but not jets as in transportation
Royals named after American Royal livestock, horse show and rodeo not person
Frank Leahy, picked the Chargers name when he purchased an AFL franchise for Los Angeles: “I liked it because they were yelling ‘charge’ and sounding the bugle at Dodgers Stadium and at USC games.”- Wikipedia.
The Thrashers are named after Georgia state bird.
Chargers are horses
Hornets is from a Revolutionary war description of a battle near Charlotte in which the Colonials defending Kings Mountain were described as fighting like hornets or later British General Cornwallis called the Charlotte area a Hornets Nest of Rebellion. Later the name Hornet becomes a Naval Ship Similarly Detriot’s light guard or militia from 1830 were named the Tigers.The team took this troop’s name. Third military connection is Boston Braves from the Boston Tea Party were Colonials “dressed” up as indians to raid the British ships in the Harbor. Insect yes but fighting spirit and named after Military connections Yes, Yes.Yes.
Finally one can also say that Angles is the english version of Los Angelos and thus the team is named after the city like the Twins and Phillies (Philadelphians). Thus three teams named after their host cities.
Also many other sports teams especially football teams were named after baseball teams such as Giants (NY Giants), Redskins (old Boston Braves), Bears (Cubs), and Titans (Giants). Basketball’s Knicks named after Baseball’s first team the NY Knickerbockers.
Interesting the Washington Redskins nickname started in Boston, when the NFL Boston Braves (first playing in Braves Field) moved to play in Fenway Park. Obviously not wanting a Braves-named team playing in an AL park, the owners changed the team name to the Boston Redskins, reflecting congruity with the Red Sox moniker and the Native American players and coach on the football squad.