This creature has a confused and troubled timeline and history. Explanations range from misidentifications  to invented stories, to regular animals with mange, to urban legend and to myth.

The first attack by a Chupacabra is said to be in March 1995 when 8 sheep were found dead in Puerto Rico. Each body had three puncture wounds in the chest area and were said to be drained of blood. More stories came from the mountain region of Morovis and Orocovis. Chickens, sheep and goats were being found dead in their pens and enclosures, drained of blood with deep puncture wounds to the neck or chest.  Nightly search parties of at least 200 men went out in search of the culprit(s) and to guard the animals. Nothing was found.

Six months later Madelyne Tolentino, a housewife, claimed to have seen the creature near the town of Canaovanas in the eastern part of the island. She described it as a fanged, furry Kangaroolike creature with bulging red eyes. More reptile-like, it was said to have leathery or scaly, greenish-gray skin and sharp spines or quills running down its back.

Author Benjamin Radford [Tracking the Chupacabra] decided after his research that Toletino's description is unreliable. It was nearly identical to the creature depicted in the 1995 horror film "Species", which she had recently viewed. "It was a creature that looked like the Chupacabra, with spines on its back and all. . . . The resemblance to the Chupacabra was really impressive," said Tolentino. According to Radford, Tolentino believed that the events and the creature from that film were real and were happening in Puerto Rico at that time.

Later reports came out of a creature with a pig-like creature or a humanoid-headed one with a tail and spikes or pointed tufts of hair running down its back. It was said the creature(s) walked erect, standing about 4 ft. high. And some said they saw clawed hands.  Some investigators tried to claim it was a Satanic Cult of some kind but no proof was ever produced.

By mid-December of 1995, people were saying that more than 1000 animals had been killed by the Chupacabra. The numbers included goats, chickens, turkeys, sheep, rabbits, cats, dogs, and even cows and horses. 

Although humans were not reported killed by the creature, there is a story from November 1995 where someone claimed a red-eyed hairy beast broke open their bedroom window, reached inside, and ripped a teddy bear to pieces.

The Puerto Rican government never denied that the attacks happened. They did, however, insist that the attacks were from wild dogs or feral monkeys. The locals did not accept the explanations offered as they knew that dogs and monkeys do not have blood sucking habits.

The blood draining was never completely confirmed. Necropsy was never done on the bodies of the animals' bodies, which is needed to determine if a body has been drained of all blood. There is a veterinarian who is said to have analyzed at least 300 of the reported victims' bodies. He denied that the bodies were bled dry.

As the attacks began to dwindle in Puerto Rico, they began to appear on the North American mainland. First reports came in late March 1996 from the Latino neighborhood of South Miami. Locals there blamed the Chupacabra for more than 60 animals deaths. This included goats, chickens, ducks and geese.

One woman claimed she saw "a doglike figure standing up with two short hands in the air." Zoologist Ron Magill insisted the marks on the victims of the attacks were "classic canine punctures from dogs.".

By late April, farmers in 11 Mexican states reported dozens of attacks. Goats were the predominant victims. The Mexican officials blamed coyotes and bats for the attacks. They were driven to these acts of desperation by the recent drought.

Attacks were also reported coming from Costa Rica, El Salvador, Guatemala, Chile, Colombia, Honduras, Nicaragua, Panama, Peru, Brazil, Dominican Republic, Argentina, Bolivia, and Amazonia. And some reports from Russia and the state of Maine.

In October 1996 a herd of 28 sheep in Idanha-a-Novo, Portugal were attacked. A local farmer claimed each animal had a single deep puncture to the left side of its neck. Nine sheep died from the attack.

By March, 2005, the Komsomolskaya Pravda newspaper began reporting the vampiric killing of sheep, turkeys and chickens in the Saraktash region of Central Russia. These attacks were said to have been made by a dog - or kangaroo-like creature with long fangs.

August 2007, a Cuero, Texas farmer Phylis Canion started to lose her chickens to a creature that was draining them of blood but was not eating them. She saw a strange, smallish, hairless doglike creature on the property that she determined might be responsible. It had long back legs and very long canine fangs. When she talked to her neighbors about the attacks and the creature she saw, she learned that three more creatures identical to the one she saw had been hit by cars or trucks.

Forensic testing on the bodies of these creatures revealed that the Cuero Chupacabra was a canine, probably a coyote-dog or coyote-Mexican wolf crossbreed. As reports made in the United States spoke of the creature as a mammal, and based on the forensic tests, the Chupacabra creature has been dismissed as dogs and coyotes with mange. This would leave the poor animals with little hair, thickened skin, and a bad smell. It's been theorized that they attack the domestic animals because of their weakened state. The goats and such are easier for them to attack than trying to chase down deer or rabbits.

Some claim the attacks could not have been done by dogs or coyotes because the attacked animals were not eaten. This may not be true. The attacking canines may be inexperienced, too ill or injured to eat or to finish the kill. The animals attacked could survive the initial encounter and then later die from their injuries or blood loss. The puncture marks on the neck are said to be the classic mark of a canine attack.

There are those who still wonder why the creatures appear to be hairless when their mammal like appearance indicates that they should have a coat of hair. They reject the notion that mange is the probable cause. Also mentioned is the physical difference of the ones found in Texas. The back legs are much longer than the front legs which gives them a kangaroo like look. This is not a common feature of dogs, coyotes or wolves. However, this physical abnormality may explain why some of the witnesses said that the Chupacabra was bipedal. Four legged animals with longer back legs often perch on them briefly to scan the area for danger or prey.

Others still puzzle over the apparent vampiric diet. It is reported the victims are not mauled or even partially eaten. Again, those people claim that canine attackers would eat at least some of their prey. Without thorough investigations, the claims are made that only the blood is taken, draining the bodies. 

Anyhow, if those critics of the usual explanations are correct, that the Chupacabra is a real creature, it remains outside of all previous scientific experience.