Largest prehistoric organisms

The largest prehistoric organisms include both vertebrate and invertebrate species. Many are described below, along with their typical range of size.

Heaviest prehistoric mammals
A list of prehistoric mammals over 10 metric tonnes.


 * 1) Livyatan (40-?70 tonnes/40.6-70.7 tons)
 * 2) Basilosaurus (38.6-?60.2 tonnes/ 40-60.8 tons)
 * 3) Basiloterus (30-?40 tonnes/31-?40 tons)
 * 4) Indricotherium (12-15 tonnes/12-16 tons)
 * 5) Deinotherium (10-14 tonnes/10-15 tons)
 * 6) Mammuthus imperator (12.5 tonnes/13 tons)

Longest prehistoric mammals
A list of all prehistoric mammals equal to or longer than 8 metres.


 * 1) Basilosaurus (18-?21 metres/59.1-?70.8 feet)
 * 2) Livyatan (13.5-17 metres/44-55 feet)
 * 3) Basiloterus (10-?13 metres/33-?42.6 feet)
 * 4) Deinotherium (8.8-12.5 metres/29-41 feet)
 * 5) Indricotherium (9-12 metres/30.8-39.3 feet)
 * 6) Zygorhiza (6-8 metres/19.6-25 feet)

Heaviest avian dinosaurs

 * 1) Dromornis australis (500 kg/1100 lbs)
 * 2) Aepyornis maximus (425 kg/935 lbs)
 * 3) Aepyornis medius (400 kg/880 lbs)
 * 4) Dinornis giganteus (278 kg/612 lbs)
 * 5) Aepyornis gracalis (250 kg/550 lbs)

Tallest avian dinosaurs

 * 1) Dinornis giganteus (3.6 m/12 ft)
 * 2) Dromornis australis (3.3 m/10.8 ft)
 * 3) Aepyornis maximus (3.15 m/10.3 ft)
 * 4) Aepyornis medius (3 m/9.8 ft)
 * 5) Aepyornis gracalis (2.8 m/9.2 ft)

Longest arthropods

 * 1) Jaekelopterus (3 m/9.2 ft)
 * 2) Arthropleura (2.5 m/8.2 ft)
 * 3) Pterygotus (2.3 m/7.5 ft)
 * 4) "Eurypterus" alveolatus (1.8 m/6 ft)

Heaviest fish

 * 1) Leedsichthys (70 tonnes)
 * 2) Carcharocles megalodon (30-?>50 tonnes)
 * 3) Helicoprion (18 tonnes)
 * 4) Dunkleosteus (?12-?15 tonnes)
 * 5) Titanichthys (?8 tonnes)

Longest fish

 * 1) Leedsichthys (16-20 m/52-66 ft)
 * 2) Carcharocles megalodon (14-?20 m/45-?66 ft)
 * 3) Helicoprion (10 m/32 ft)
 * 4) Dunkleosteus (9 m/29.7 ft)
 * 5) Titanichthys (?6 m/19.6 ft)

Longest amphibians

 * 1) Prionosuchus (9 m/29.7 ft)
 * 2) Eogyrinus (5 m/16 ft)
 * 3) Koolasuchus (4.5 m/15 ft)
 * 4) Mastodonsaurus (4.3 m/14 ft)
 * 5) Anthracosaurus (3.6 m/12 ft)

Heaviest reptiles

 * 1) Shastasaurus (60 metric tons/66 short tons)
 * 2) Shonisaurus (50 metric tons/55 short tons)
 * 3) Predator X (45 metric tons/49.5 short tons)
 * 4) Pliosaurus (35 metric tons/38.5 short tons)
 * 5) Liopleurodon (10-?20 metric tons/11-?22 short tons)
 * 6) Deinosuchus (9 metric tons/10 short tons)
 * 7) Sarcosuchus and Mourasuchus (7 metric tons/7.75 short tons)

Longest reptiles

 * 1) Shastasaurus (21 m/69.3 ft)
 * 2) Shonisaurus (15 m/49 ft)
 * 3) Predator X (15 m/49 ft)
 * 4) Pliosaurus (13 m/43 ft)
 * 5) Deinosuchus (12 m/40 ft)
 * 6) Sarcosuchus and Mourasuchus (12 m/40 ft)
 * 7) Liopleurodon (11 m/36 ft)