LSAT 90 - Section 2 - Question 05

This is an RRE question.

The stimulus tells us that individual zebras aren't very well camouflaged in their habitat. On the African plains where it lives, the vegetation tends to be green or brown, but the zebra has black and white stripes. This failure to camouflage makes zebras stand out to lions that hunt them. So the stimulus says that it's surprising that zebras survive.

As with any RRE question, the stimulus presents a phenomenon which is a set of facts in need of an explanation. Whether or not there is anything surprising about the phenomenon largely turns on what naïve assumptions we make. Here, if we simply refrain from making any assumptions, then it isn't surprising that zebras survive with such vivid markings. We simply have to be open-minded to the possibility of some explanation for how the zebras can survive even though their stripes make them stand out.

Correct Answer Choice (E) says that when zebras run in a group, as they generally do in response to danger, the stripe markings make it difficult for predators pursuing a single individual to discern its outline. This phenomenon resolves the problem in the stimulus. The fact that individual zebras stand out from the landscape now seems irrelevant because zebras tend to run in groups, and when they are in a group, their stripes create the effect of blurring the boundaries between any individual zebra and the group as a whole. That's an advantage for the individual zebra in terms of getting away from a predator. All we need to assume is that if it's difficult for a predator to discern an individual zebra, then it's difficult for that predator to effectively catch the zebra.

Using the naïve assumption framework, the phenomenon above only seems puzzling if we naïvely assume that an individual zebra's stripes making the zebra stand out from the landscape is all there is to the story; in other words, if we assume that there were no other causal factors at play. But why would we assume this? This is why I said as long as we keep an open mind about the complexity of the story, we shouldn't really feel a sense of surprise.

Answer Choice (A) says because the vegetation on open plains changes from green to brown as the season changes from wet to dry, true camouflage coloring for prey would have to change according to the seasons. This explains nothing. The zebra stripes are black and white, neither of which is green or brown. The stimulus already told us that the vegetation is green or brown. That's what makes the zebra stand out. This answer choice merely tells us that the vegetation changes from green to brown. But whether the vegetation was statically green or brown or dynamically green or brown doesn't change the fact that the zebras stand out.

Answer Choice (B) says that zebras are able to judge from the demeanor of lions whether or not those lions are preparing to hunt, and the zebras ignore the ones that don't intend to hunt. This is also irrelevant. This phenomenon may explain why zebras can sometimes be found within lions' hunting range, because the zebras know that these lions are not a threat. But it has no bearing on the phenomenon we're actually trying to explain, which has to do with its black and white stripes making it stand out.

Answer Choice (C) says lions that hunt zebras are themselves colored in a way that blends in with the brown color of dry vegetation, so that in the dry season, when prey is scarce, the lions can creep up on their prey to a distance from which lions have a favorable chance of succeeding in the hunt. Okay, so this answer explains the lion's coloration and coat pattern. But we're trying to explain the zebra's coloration and stripe patterns.

Answer Choice (D) says when lions hunt, the whole pride shares in the food obtained when a prey animal is successfully brought down by one of the hunting lions. I don't even know where to start with this answer. Lions are just a little bit socialist. Good for them. What does this have to do with zebras having black and white stripes?