Definition

Noun: A ratite is a type of large, flightless bird characterized by a flat, raft-like breastbone (sternum) that lacks a keel. The keel is the ridge found in flying birds where powerful flight muscles attach. Ratites are a diverse group that includes some of the world's largest birds.

Usage and Examples

• Noun:
  • The ostrich, a well-known ratite, is the world's largest living bird.
  • Ratites like the emu and cassowary are native to Australia and New Guinea.
  • Scientists study the evolution of ratites to understand how flightlessness developed in different continents.

Advanced Usage

• In Scientific Classification: The term "ratite" is often used in contrast with "carinate" (birds that have a keeled sternum and are typically capable of flight). It refers to birds in the infraclass Palaeognathae that share this specific anatomical trait.
  • The debate continues on whether the flightlessness of ratites evolved from a common flightless ancestor or independently.

Variants and Related Words

• Ratitous (adjective, rare): Pertaining to or characteristic of ratites.
  • The ratitous sternum is a key identifying feature.

Synonyms

• Flightless bird (This is a broader, more general synonym. Not all flightless birds are ratites—e.g., penguins are flightless but have a keeled sternum and are not ratites.)
• Palaeognath (This is a broader taxonomic term that includes both flightless ratites and the flying tinamous.)

Related Terms and Concepts

• Keel (Carina): The prominent ridge on the breastbone of most birds, absent in ratites.
• Palaeognathae: The infraclass of birds that includes both ratites and tinamous, characterized by a primitive palate structure.

Noun

1. flightless birds having flat breastbones lacking a keel for attachment of flight muscles: ostriches; cassowaries; emus; moas; rheas; kiwis; elephant birds