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Is It True That T. Rex Could Only See Things That Were Moving?

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I rewatched Jurassic Park a few weeks ago and, from the story to the special effects, it still holds up. But I’ve been nagged by one thing that’s stuck with me from the first time I saw the movie—a thing that has been ingrained in our collective knowledge and perception of dinosaurs: protagonist Alan Grant's assertion about what the Tyrannosaurus rex can and can’t see.

In the scene where the T. rex gets loose and attacks a group of human characters, Grant says to Lex, “Don’t move. It can’t see us if we don’t move.” Sure enough, the dinosaur gets up in their faces without noticing them right after he says that. For what it's worth, Michael Crichton does explain in the Jurassic Park novel that the amphibian DNA used to help bring the dinosaurs to life hobbled their visual cortices. Director Steven Spielberg and the movie's screenwriters dropped the ball big time here, importing the dinosaurs’ vision problems but not the explanation for them. Instead, in the movie, Grant comes off like he’s stating an accepted dino fact.

Sci-Fi versus Reality

He’s not. In the last few years, real-world paleontologists have proven Dr. Grant very wrong. In 2006, Kent Stevens from the University of Oregon did an experiment inspired by that very scene to figure out what sort of binocular range (the field of view both eyes can see simultaneously) T. rex might have had. The wider that range, the better an animal’s depth perception and capacity to distinguish objects that are motionless or camouflaged.

Stevens built a scale model of the T. rex’s head and popped in some taxidermic eyes based on the eyes of three animals pretty closely related to T. rex—alligators, ostriches, and eagles—and adapted for situations that a dinosaur would have likely encountered. As he explains on his website, he used a technique called “inverse perimetry” to estimate “whether a given probe would be visible, based on whether there is a clear, unobstructed view of the pupil along a line of sight,” and mapped the model’s field of view.

Stevens' model study suggests that T. rex had a binocular range of around 55°, better than that of modern-day hawks and eagles. And it would have only gotten better. Paleontologists know from the fossil record that, over millennia, T. rex’s eyes got larger and its snout got lower and narrower, giving it even clearer sight lines than Stevens’ model.

For more on dino-vision, see Stevens' web page and the study. For more on other JP mistakes that make dino geeks fume, see this Wikipedia list.

What’s the Difference Between Prison and Jail?

Many people use the terms jail and prison interchangeably, and while both terms refer to areas where people are held, there's a substantial difference between the two methods of incarceration. Where a person who is accused of a crime is held, and for how long, is a factor in determining the difference between the two—and whether a person is held in a jail or a prison is largely determined by the severity of the crime they have committed.

A jail (or, for our British friends, a gaol) refers to a small, temporary holding facility—run by local governments and supervised by county sheriff departments—that is designed to detain recently arrested people who have committed a minor offense or misdemeanor. A person can also be held in jail for an extended period of time if the sentence for their offense is less than a year. There are currently 3163 local jail facilities in the United States.

A jail is different from the similarly temporary “lockup”—sort of like “pre-jail”—which is located in local police departments and holds offenders unable to post bail, people arrested for public drunkenness who are kept until they are sober, or, most importantly, offenders waiting to be processed into the jail system.

A prison, on the other hand, is usually a large state- or federal-run facility meant to house people convicted of a serious crime or felony, and whose sentences for those crimes surpass 365 days. A prison could also be called a “penitentiary,” among other names.

To be put in a state prison, a person must be convicted of breaking a state law. To be put in a federal prison, a person must be convicted of breaking federal law. Basic amenities in a prison are more extensive than in a jail because, obviously, an inmate is likely to spend more than a year of his or her life confined inside a prison. As of 2012, there were 4575 operating prisons in the U.S.—the most in the world. The country with the second highest number of operating prisons is Russia, which has just 1029 facilities.

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What Do Morticians Do With the Blood They Take Out of Dead Bodies?

Zoe-Anne Barcellos:

The blood goes down the sink drain, into the sewer system.

I am not a mortician, but I work for a medical examiner/coroner. During an autopsy, most blood is drained from the decedent. This is not on purpose, but a result of gravity. Later a mortician may or may not embalm, depending on the wishes of the family.

Autopsies are done on a table that has a drain at one end; this drain is placed over a sink—a regular sink, with a garbage disposal in it. The blood and bodily fluids just drain down the table, into the sink, and down the drain. This goes into the sewer, like every other sink and toilet, and (usually) goes to a water treatment plant.

You may be thinking that this is biohazardous waste and needs to be treated differently. [If] we can’t put oil, or chemicals (like formalin) down the drains due to regulations, why is blood not treated similarly? I would assume because it is effectively handled by the water treatment plants. If it wasn’t, I am sure the regulations would be changed.

Now any items that are soiled with blood—those cannot be thrown away in the regular trash. Most clothing worn by the decedent is either retained for evidence or released with the decedent to the funeral home—even if they were bloody.

But any gauze, medical tubing, papers, etc. that have blood or bodily fluids on them must be thrown away into a biohazardous trash. These are lined with bright red trash liners, and these are placed in a specially marked box and taped closed. These boxes are stacked up in the garage until they are picked up by a specialty garbage company. I am not sure, but I am pretty sure they are incinerated.

Additionally anything sharp or pointy—like needles, scalpels, etc.—must go into a rigid “sharps” container. When they are 2/3 full we just toss these into one of the biotrash containers.

The biotrash is treated differently, as, if it went to a landfill, then the blood (and therefore the bloodborne pathogens like Hepatitis and HIV) could be exposed to people or animals. Rain could wash it into untreated water systems.

This post originally appeared on Quora. Click here to view.


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