Slowly but surely, the idea that deinonychosaurs ("raptors") had feathers is reaching the minds of the public. Compared to past years, here have hardly been any complaints about feathered deinonychosaurs on Wikipedia so far this year.

However, at least some people must still have some misgivings about feathered deinonychosaurs, because they try to compromise. They give their deinonychosaurs a fuzzy mane down the neck or a crest of feathers on the head or a few strands of protofeathers on the arms and leave everything else scaly.

Oops, that still doesn't cut it.

Previously, I've done a piece on common anatomical errors made when drawing deinonychosaurs, but this time I'll focus on the plumage.

For one thing, almost all of a deinonychosaur's body would've been covered in pennaceous feathers. The very tip of the snout (not the entire snout, just the tip) is the only area that's free of feathers in all deinonychosaurs with known integument, and in many, the lower legs (below the ankles) or feet are scaly as in birds, but the maybe-deinonychosaur Anchiornis huxleyi even has feathered toes. The fingers are commonly shown as scaly in many renditions, but this is incorrect. Even the fingers were feathered! We also know that some deinonychosaurs, like Microraptor zhaoianus, had head crests that may have been formed by pennaceous feathers. It is plausible that the largest deinonychosaurs had some bare areas (likely the legs, flanks, and neck, as in big flightless birds), but there is no good reason to suppose any deinonychosaur lost its feathers altogether. (And remember, those bare areas wouldn't have been scaly. They're just naked skin.)

Deinonychosaurs had longer pennaceous feathers on the wings and tail as well, similar to modern birds. A lot, if not most, pictures of feathered deinonychosaurs give them secondaries (feathers on the lower arm), which is good because they had those. However, they also had primary feathers. Let me rephrase that.

Deinonychosaurs had primary feathers deinonychosaurs had primary feathers deinonychosaurs had primary feathers deinonychosaurs had primary feathers deinonychosaurs had primary feathers deinonychosaurs had primary feathers deinonychosaurs had primary feathers deinonychosaurs had primary feathers deinonychosaurs had primary feathers deinonychosaurs had primary feathers.

I've lost count of the time where otherwise good images of deinonychosaurs have no primary feathers. Primary feathers are the feathers which attach to the second finger, so a correct deinonychosaur image would show part of its hands hidden behind the primaries. If you see one that shows its hands exposed in full view, that is wrong! However, deinonychosaurs did not have tertials. Those are the big feathers on the upper arm. They just had shorter feathers there. A deinonychosaur with fully extended wings will leave a gap between the wings and body.

At least some deinonychosaurs had long pennaceous feathers on the legs, too, forming a second pair of wings. This trait may be ancestral to the group, but some other deinonychosaurs may or may not have lost it. I usually draw all deinonychosaurs with at least rudimentary hind wings, but we don't know much about those yet.

The pennaceous feathers of the tail are restricted to a fan on the tip in dromaeosaurids (the more robust "raptors"), but are found all along the tail in troodonts (the more gracile, longer-legged "raptors").

One more thing to remember: if you look at modern birds, their skeletons barely match their living bodies because they have so many feathers. In life, feathers hide a lot of skeletal features, so it's best to make feathered deinonychosaurs look somewhat bigger and plumper than you'd expect from their skeletons, with no obvious S curve in the neck.