How many party members can a Giant Eagle carry?

Question

In an online video, Dungeon Dudes state that the Polymorph spell can be used to polymorph a party member into a Giant Eagle which could carry the entire party if the number of party members was low - but they didn't mention how low.

A party might want to evacuate an area using this technique. How many total party members can a Giant Eagle carry? (i.e. mounted and carried)

Answer 1

No more than four, weighing no more than 480 lbs., and with caveats

The basic carrying rules would yield a maximum load of 480 lbs. (16 × 15 × 2) given the giant eagle's stat block (Large size, Strength 16).

Carrying Capacity. Your carrying capacity is your Strength score multiplied by 15. This is the weight (in pounds) that you can carry, which is high enough that most characters don't usually have to worry about it.

and

Size and Strength. Larger creatures can bear more weight, whereas Tiny creatures can carry less. For each size category above Medium, double the creature's carrying capacity...

But if your game uses the variant encumberance rule, then you would be subject to the associated drawbacks listed therein when your eagle's load reaches

• 160 lbs: speed becomes 70 (reduced by 10)
• 320 lbs: speed becomes 60 (reduce by 20) plus your eagle has "disadvantage on ability checks, attack rolls, and saving throws that use Strength, Dexterity, or Constitution".

Then there is the question of how many can fit mounted vs. carried. The basic rules regarding mounts state that you can use a creature as a mount to the extent that it has "appropriate anatomy." So your DM would make a ruling on that as well as how many the eagle can grab, and (assuming all are medium humanoids) the most generous ruling I can imagine would be two mounted riders and two additional "passengers" clutched by talons, such that all of them total no more than 480 lbs.

More Caveats

• Don't forget that your giant eagle would lose its Talons attack while fully loaded in this way.
• Assuming your eagle is intelligent and cooperative (a polymorphed or wild-shaped player) then your DM might not require an Animal Handling check for riders, but still might require other Skills checks (such as Athletics or Acrobatics) to stay mounted on an eagle that is making aerial maneuvers.
• Furthermore, you really need an Exotic Saddle to be riding a flying mount, as addressed in this question. Better pack one ahead of time if you want to try this trick!

Answer 2

Issue of Anatomical Interpretation - a case for 1 rider

As Valley Lad notes, the carrying capacity of a giant eagle is sufficient to convey a good number of players - the main limitation is "appropriate anatomy".

A riding horse has the same size and strength as a giant eagle. Horses have been bred for thousands of years to have an anatomy ideal for riding, and yet two riders on one back is quite a squeeze. A giant eagle has no such pedigree, and we might be able to assume that much of its "large" size is owed to its wing span, where as a horse's size is almost all torso. Note that a medium sized creature occupies 5'x5' area on a battlemap, and a large occupies a 10'x10' area.

The only other guidance on mount qualification is that it must be one size larger than the rider. A medium creature (human) can ride a large creature (giant eagle), for example. There is no RAW rule against this, but it intuitively feels wrong for a mount to be ridden by many creatures only a single size category larger than it. Four Medium-sized creatures on a Huge mount perhaps, but on a Large?

However, if all of the players were put in a basket carried by the eagle, I believe there is no question of anatomical limitation: in that case the number of passengers would only be limited by carrying capacity.