No worries here... I'm just walking on by, nothing to be afraid of...

Picture this picture... A stereotypical image of prehistory I am certain you've seen before... A wide-open flood plain (mountains and trees in the far distance) being traversed by a herd of Alamosaurus (sauropods) that are being attacked by a marauding flock of Tyrannosaurs rex. Although many usually find such images and the stories of what they depict to be the awesomest thing they had ever seen / read, my opinion is a bit different. For the sake of posterity, here's why...

We tend to underestimate these animals, probably in favor of the fantastic battles of the movies and of the books we grew up with... Exactly like that described above. As with other "super sauropod killers", such as Giganotosaurus, these "Southern Rexes" were most likely sauropod specialists (same applies for the "Northern Rexes" that were hunting ceratopsians, hadrosaurs, etc.)... In other words, given the levels of risk involved, they surely knew exactly where to deliver precise, crippling blows to quickly dispatch large, dangerous prey animals, minimizing their own exposure to injury and / or death. We should be suspicious of scenarios having prolonged battles (the mammalian bias) and sit downs (the Komodo Dragon bias), or which insinuate a tactic of full-hearty volleys that place predators who are on the losing end of a size disparity in compromised positions. Therefore, such pictures as described above, although often wonderful pieces of Paleo art accompanied by exhilarating stories, are probably unrealistic / fantastical in their representation of an actual hunt. In fact, the Chased by Dinosaurs episode with Giganotosaurus and Argentinosaurus, and The Ballad of Big Al and its salt flat attack scene are perfect examples of such unlikely scenarios.

[Insert here, a defensive comment from the artist / author about how animals will risk life and limb to avoid "dying from hunger".]

Meh... Does every attack always have to be a desperate, dramatic, "dying from hunger" scenario? For a barely semi-legitimate comparison's sake, consider lions and elephants in this study: Joubert D. 2006. Hunting behaviour of lions (Panthera leo) on elephants (Loxodonta africana) in the Chobe National Park, Botswana. Afr J Ecol 44:279-281. Bottomline is that lions are rather careful about attacking something so much larger than themselves (and I'm sure there is a "dying from hunger" scenario in there someplace, as failed attempts don't do much in the way of fulfilling a lion's energy requirements). Basically, lions employ a similar tactic as used on other large prey animals (think cape buffalo), where attacks are AMBUSH attacks (i.e not exposed out in the open) from the rear of the selected elephant, the majority of which are subadult animals (younger still have attentive adults, and I imagine smaller animals are easier to handle, in general). In that same vein, maximum non-visibility is a factor, especially if adult animals are targeted, as a fair number of such attacks in the study occurred during low-light hours (all but 1 attack on an adult was at dusk / night... the adult attacked during the day was suffering from an injury received during a fight with another adult elephant).

During an attack, lions position themselves at the furthest possible place away from an elephant's defenses. The usual modus operandi is to target herd stragglers (nearly half killed in the study were some 50 m away from the main herd), but if not, a tactic of panic is employed to bunch elephants in an effort to apparently make them cause injury to themselves (i.e. cause one to fall, get crushed, etc.). And that's about where a comparison of big mammal - big dinosaur tactics ends, because a theropod who held on to a sauropod (or a ceratopsian, etc.), was a dead theropod. As for success rate and assessment of risk to the lions... Over the course of 4 years and 323 attempts, only 74 were successful kills, with only 1 lion being seriously injured... and that injury was accidental, rather than a result of a defensive move on behalf of the elephant (the elephant fell the wrong way, landing on top of a lion, which apparently survived the initial injury, at least). Unfortunately, the study doesn't specify how many lions were usually involved in an attack.

So, the lesson here is that, cautious, low-risk predation tactics is the order of the day when it comes to the interaction between two of today's largest terrestrial animals, and this most likely applied to our beloved extinct titans as well.

Ballad of Big Al salt flat attack scene

Image on the left: ©Gregory S. Paul.    Image on the right: ©Damir G. Martin.