Background

This is a Terror Bird:

Specifically, this is Titanis one of the largest of the carnivorous Phorusrhacidae; it was perhaps 2.5 meters tall and 150 kg.

I would like a terror bird that is at least 1000 kg, but it would be even better if it were more like 5000 kg; the size of a Tyrannosaurus. Fundamentally, Tyrannosaurus is more closely related to bird than it is to extant reptiles like crocodiles. Of all the birds that we know of, the terror birds come closest to matching the physical anatomy of Tyrannosaurus; that main difference being that the birds lack the heavy tail of Tyrannosaurus.

Question

Two overlapping questions:

• Can a terror bird weighing 1000 kg survive in any modern ecosystem?

• Can a terror bird weighing 5000 kg survive in any modern ecosystem?

Considerations

• Modern ecosystem means anything that exists today, though assume that human hunting pressure doesn't exist so herds are plentiful.
• A modern physical environment means current temperatures and oxygen concentrations, among other things. There is some speculation that higher oxygen levels could be related to dinosaur size. I want to be sure that a terror bird shape can bio-mechanically be extended to large enough size.
• The terror bird must be able to survive at all sizes as it grows (at whatever rate it can) into a full sized adult.
• Given that terror birds are probably extinct due to competition with modern modern predators, assume that the terror bird can successfully compete with modern carnivores (lions, etc).
• Do not assume that a terror bird can catch modern herbivores (can it catch a horse?) This an important part of the question.

posted over 6 years ago

kingledion‭

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