Simplify the following text for a Grade 4 native English-speaking person.
Original: The largest species , including the mute swan , trumpeter swan , and whooper swan , can reach length of over 1.5 m ( 60 inches ) and weigh over 15 kg ( 33 pounds ) .
Simplified: The Mute Swan , Trumpeter Swan , and Whooper Swan are the largest swans . They can be over 1.5 m ( 60 inches ) long .