Night images can often be blurry and lacking in sharp focus, but still hold a viewer's attention.

Many of the cameras were attached to trees, but didn't stay put. Others didn't survive their encounters with curious, hungry or aggressive wildlife - with some getting chewed on, tossed about or destroyed.

Alexandra Swanson, a researcher, suspects that the cameras carried a human odor, which made some animals more aware of them than others, leading them to be inspected or scent-marked.

The researchers had to frequently swap out memory cards and batteries for the cameras since the cameras fire around the clock creating so many images.

The tricky part is identifying the content of the images. The researchers decided to take advantage of crowdsourcing to help analyze the approximately 1.9 million images and counting. They created the online archive Snapshot Serengeti that allows people to help classify the animals. Researchers use an algorithm to help filter out inaccurate information.

There were concerns expressed that incandescent flash cameras could startle animals, but the study has proven that it doesn't keep the same animals from returning to the camera location night after night.

The heat-triggered cameras sometimes capture beautiful compositions.

Some of the images offer startlingly close-up details.

Some animals have proved to be curious about the cameras and engage with them, sometimes much to the cameras' detriment. Researcher Alexandra Swanson told The New Yorker that she has a "whole collection of the-last-photo-taken-by-this-camera photos."

Animals silhouetted. The cameras are fired by heat triggered, passive infrared sensors.

Though the cameras are set to trigger when an object warmer than the ambient temperature moves in front of the sensor, tall sunlit grass could also trigger the camera when it sways with the wind.

A hyena caught in the act. Snapshot Serengeti is studying over 30 species as part of the camera trap project.

The cameras document details of some animals.

Serengeti National Park covers an area of 5,700 square miles.

The Serengeti Lion Project has been working in the Serengeti and the Ngorongoro Conservation Crater since the 1960s. At any given time, they track about 330 lions in 24 prides in the Serengeti and 50 to 60 lions in five prides on the floor of the Ngorongoro Crater. They created the camera trap survery to collect information about other species to learn more about how they interact with each other and the lions.

Not only did the cameras catch the wildlife but also changing conditions that can make life in the Serengeti such a challenge.

Several images make it seem like the animals are posing for the camera.

The camera also took several closeups of the animals, showcasing features like their eyes.

Though not perfectly composed, the image of a giraffe's legs has its own unique aesthetic.

This is one of several images not only showing the beauty of the animals but the landscape where they live.

A hippo triggers a night shot.

A beautiful action photo.

An animal tries to take a bite out of a camera trap.

A backside view.

An elephant at night.

Wildebeest run past the camera with a helium balloon in the distance.