Approximately how fast were the terror birds theorized to run?
Answer
Around 48 km/h (30 mph)
Fossil evidence suggests they were very fast runners, with theories putting their top speed around 48 kilometers per hour (30 miles per hour).

Related Questions
What defined the Phorusrhacids' role in the Cenozoic South American ecosystem?What specific feature of the terror bird's skull anatomy was optimized for powerful strikes without excessive weight?Approximately how fast were the terror birds theorized to run?What paleontological evidence confirmed the terror bird's functionally didactyl foot posture?What weapon was located on the third, elevated toe of the terror bird?To which modern, smaller, ground-dwelling bird are the Phorusrhacids related?What anatomical feature of the neck suggested extreme flexibility for striking?What is considered the more probable primary driver for the extinction of most larger South American phorusrhacids?How did the terror bird's likely killing method differ from that of large felids?Which geological event allowed large placental carnivores to cross from North to South America?