| 1 | The liquid excreted through the urethra or cloaca. | |
| 2 | The type of the cloacal epithelium of duck was studied by using histological techniques. | |
| 3 | Modern ornithologists and herpetologists call this a "cloacal kiss." | |
| 4 | Dinosaur copulation was most likely accomplished by means of "kissing cloacae." | |
| 5 | Most male birds like turkeys and roosters have a cloaca (also present on the female), but not a penis. |