D&D General Things to Find in a Large River?

[Lanefan]

Water.

 

[Lidgar]

Giant gar

Shambling mounds and frogglemoths

A skiff manned by Halfling traders

Assassin vines

 

[Tonguez]

Swirling currents, whirlpools, eddies, undertows, snags, silt flows and tumbling rocks

 

[Yaarel]

Its all about crocodiles and hippopotamuses.

Maybe make the bronze dragon a monstrous crocodile.

Make something like the tarrasque a monstrous hippopotamus.


Nile crocodile.
Hippopotamus.

15 kinds of venomous snakes (horned viper, various cobras, ...).
Egyptians depicted winged snakes (and Herodotus claimed to have seen the skeleton of one in Egypt)

7-foot long Nile monitor lizard.
Soft-shell turtle.
Black rhinoceros.
Many fish (perch, catfish, lungfish, ...).
Many birds (ibis, kingfisher, Egyptian vulture, hawk, ...).
Many insects (scarab beetle!, locust, ...).

So many species of wildcats!
The wild cat (Felis silvestris) origin of domesticated cats.
Swamp cat (Felis chaus).
Sand cat (Felis margarita).
Cool looking caracal (Felis caracal).
Many others.

Various species of jackal, wolf, and fox.
Red Fox (Vulpes vulpes).
Somehow Ruppells Sand Fox (Vulpes rueppelli) is both cute and spooky.
Blandfords Fox (Vulpes cana).
Insanely adorable Fennec Fox (Vulpes zerda).

In Egypt and possibly near Nile:
Leopard!
Cheetah!
Even lion, but not today.
Nubian ibex.

 

[Draegn]

Bridge supports.

 

[David Howery]

I want to say piranhas, but wrong continent. Ah heck, put them in anyway....

 

[Yaarel]

I want to say piranhas, but wrong continent. Ah heck, put them in anyway....

Make the flying locusts the piranhas.

 

[David Howery]

I did use piranhas once in an Amazon jungle-ish type adventure, where the PCs were looking for a lost pirate ship, which turned out to be sunken in a wide river pool... the hardest part of the adventure was finding a way around the zillion and one piranhas in the pool.
For a Nile River-ish type adventure, crocodiles and hippos seem more apt, along with giant perch maybe, as others on here said earlier...

 

[Bohandas]

*Crocodiles
*various skiffs/rafts/barges/riverboats, carrying travelers, merchants, messengers, officials, etc.
*the missing piece of Osiris
*a child in a basket
*reverse-vampires wading through the running water in the tropical sun
*hippos
*white marbles
*sobek the crocodile god
*Brendan Fraser
*dead bodies
*herons
*ibises

 

[Son of the Serpent]

@Bohandas

the missing piece of Osiris (hah. Oh you...)

reverse-vampires wading through the running water in the tropical sun (please explain this to me a bit)