A mother and son playfully interacting is a much-cherished moment.

But even more so when it is the first time the behaviour has ever been recorded, such as the moment when a 17-month-old giant armadillo known as 'Alex' was recently captured interacting with his mother.

“Before this study we did not know how many young a giant armadillo had, and much less when they would disperse,” said Dr Arnaud Desbiez, field researcher from the Royal Zoological Society of Scotland, and coordinator of the Pantanal Giant Armadillo Project, Brazil.

“I have just returned from the field... and Alex is still in his mother's territory. Although they do not share a burrow every night, at 17 months old he still uses the burrows his mother has dug and they continue occasionally sharing a burrow,” Dr Desbiez added.

According to Dr Desbiez, Alex is becoming somewhat of a local celebrity, but this latest discovery indicates just how little is known about the species.

“We were surprised to learn how high parental investment was. This new information is extremely important and demonstrates how rare, and how much care each baby giant armadillo requires.

“Females therefore produce very few young and each animal is extremely precious,” added Dr Desbiez.

“This explains why giant armadillos have gone locally extinct in so many areas throughout their range. Too few young are born and the removal of any individual has huge consequences on the population.”

Giant armadillos (Priodontes maximus) are listed as Vulnerable on the IUCN Red List of Threatened Species and are, as their name suggests, the largest species of armadillo.

Weighing in at nearly 50kg and reaching 1.5m in length, they represent one of the largest animals in South America about which so little information is known.

Their cryptic behaviour and low population densities mean studying them has been difficult – in fact, most of what we do know about giant armadillos is anecdotal.

Elusive inhabitants

“In our study area in the Pantanal, almost none of the local people – some of them living in the area for their entire lives – had ever seen the species before the project started,” explained Dr Desbiez.

But the camera traps funded by North American and European zoos that are being used by Dr Desbiez and his team have already revealed many new insights into the secret lives of giant armadillos.

In 2013, the team discovered that giant armadillo burrows are an important shelter and thermal refuge to over 25 species ranging from tiny lizards to large collared peccaries (medium-sized hoofed mammals that resemble pigs).

According to the research team, the fact they are ecosystem engineers – animals that modify or create habitats for other species – is another example of the importance of giant armadillos in their habitat.

There are so many more questions to be answered.

News of the latest discovery was welcomed by the team at Chester Zoo, one of the organisations that helped fund the cameras used in the project.

"As a zoo that’s serious about wildlife conservation and science we’re thrilled to play a part in unearthing fascinating new discoveries," said Scott Wilson, head of field programmes at Chester Zoo.

"When scientists engage in research, there is no guarantee as to what the outputs and impacts will be. But the cameras have provided us with additional information on the lives of these secretive animals and this is all data that can inform future conservation activities."

Dr Desbiez added: “This is a long-term project and we will continue monitoring animals in our study area. We need to know [giant armadillo] inter-birth rates and understand dispersion of the young… there are so many more questions to be answered.”

You can follow Ben Aviss on Twitter and BBC Earth on Facebook, Twitter and Instagram.

Find out more about the Giant Armadillo Project in Brazil.