Mass strandings of whales occur on beaches near military exercises where sonar is used, raising concerns about the effects of human-generated underwater sounds on animal behavior. Scientists are collecting behavioral data on several species of whales to find out how sonar affects them. Researchers followed tagged blue whales to observe how they respond to simulated military sonar—using sound levels much lower than those typically used during military exercises. Analyze the sample of data below for one individual blue whale and summarize the behavioral effect of the sound exposure.

Video transcript

Welcome back. Let's look at the next question here, ants use pheromones to direct the colony to food sources when the food is rich, each ant will deposit pheromones on the trail as they move to and from their colony when the food runs out, how will they communicate this with the other ants? Well, when the food sources rich, as the question tells us, the ants deposit pheromones to and from the food source, and this leads an uh strong trail that will lead increasing number of ants to follow that trail, depositing their own pheromones. That encourages the ants in the colony to go to richer food sources. Um But as the food runs out, the ants on their way back no longer deposit pheromones. So the end result is that that trail becomes weaker because instead of having the depositing pheromones to and from there, only depositing pheromones on the way, they're not on the way back. As the trail becomes weaker, the ants are diverted to stronger trails, fewer and fewer ants follow, that trail becomes weaker still eventually the ants stop going that way and that so that essentially has the effect of letting the ants know the food sources run out and they will no longer go in that direction. So, let's look at the answers choices here. Choice A says they produce other chemicals. Well, that's not our answer. They're still depositing the same pheromones. Just fewer of them. Choice B says they will stop adding pheromones to the trail, letting them fade out. Well, that is a correct description of what happens. So. Choice B. Is our answer here, he says. They provide sound cues to warn other ants know they keep on using pheromones. Choice D. They provide visual signals to let other ants know that the food source has been depleted again. No, they keep on communicating just by means of those chemical pheromones. So again, how does the how do they communicate with other ants that the food has run out? Choice be? They will stop adding pheromones to the trail, letting them fade out. See you in the next video.