# Bonnethead (*Sphyrna tiburo*)

> The bonnethead (Sphyrna tiburo) is the smallest hammerhead shark and the only shark known to eat substantial seagrass. Adults reach 1.5 m, inhabit warm shallows, and are listed Endangered.

- **Category:** Fish
- **Conservation status (IUCN):** Endangered
- **Range:** Shallow coastal waters of the western Atlantic and eastern Pacific.
- **Canonical page:** https://globalanimalguide.org/animals/bonnethead/
- **Last reviewed:** 2026-07-16

## Scientific classification

- **Kingdom:** Animalia
- **Phylum:** Chordata
- **Class:** Chondrichthyes
- **Order:** Carcharhiniformes
- **Family:** Sphyrnidae
- **Genus:** Sphyrna

## Facts at a glance

| Attribute | Value |
| --- | --- |
| Scientific name | Sphyrna tiburo |
| Diet | Omnivore (crustaceans and seagrass) |
| Habitat | Seagrass beds and estuaries |
| Lifespan | 15–20 years |
| Weight | 8–15 kg |
| Top speed | up to 30 km/h |
| Conservation status | Endangered (IUCN) |

## Shovel-headed omnivore

A rounded cephalofoil — not the classic T-hammer — houses electroreceptors for finding prey buried in sand. Digestive enzymes process both crustaceans and seagrass.

## Crabs, shrimp, and seagrass

Blue crabs and shrimp dominate carnivorous meals, but gut studies show significant seagrass digestion — rare plant-eating among sharks.

## Western Atlantic and eastern Pacific shallows

Estuaries, mangroves, and seagrass beds from New England to Brazil and in the Gulf of California. Warm, coastal nursery fidelity defines ecology.

## Endangered in bycatch nets

IUCN lists bonnethead Endangered. Gillnets and shrimp trawls kill large numbers; seagrass loss removes feeding habitat.

## Frequently asked questions

### Do bonnethead sharks eat plants?

Yes — they digest seagrass with enzymes, making them the only known omnivorous shark.

### How is a bonnethead head shaped?

A smooth, rounded hammer — narrower than great hammerheads — like a shovel.

### Where do bonnetheads live?

Warm shallow coastal waters of the western Atlantic and eastern Pacific.

### Why is the bonnethead Endangered?

Heavy bycatch in coastal fisheries and seagrass habitat degradation.

### Are bonnetheads dangerous?

Bites are very rare; they are small coastal sharks focused on crabs and seagrass.

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Source: Global Animal Guide (https://globalanimalguide.org/animals/bonnethead/). Licensed CC BY-NC 4.0 — free for non-commercial reuse with attribution.