It is the first confirmation that Julen is down the 110-metre (360-foot) deep shaft after family members said he tumbled in on Sunday while playing as his parents had lunch nearby.
“We found a little hair (in the well) and the DNA tests carried out by the Civil Guard certify that they belong to the child,” Alfonso Rodriguez Gomez, a government representative of the southwestern region of Andalusia, told news radio Cadena Ser.
The boy's father Jose said the discovery meant he and Julen's mother could “see a little light”, adding that they felt “dead, but with hope for an angel to help us bring him back alive”.
Firefighters had previously found a bag of sweets in the well, but two cameras lowered into the shaft failed to capture any trace of him.
?Damos todo nuestro apoyo y esperanza a la familia del pequeño de 2 años que se cayó en un pozo en la localidad malagueña de #Totalán
— AUGC Guardia Civil (@AUGC_Comunica) January 13, 2019
“There is hope he's alive but it diminishes with each passing minute,” said Miguel Angel Escano, the mayor of Totalan, the closest town to the well.
Rescue teams are digging two tunnels, one parallel to the well and another at an angle aiming to reach where the child is believed to have fallen.
El dispositivo de búsqueda y rescate del pequeño #Julen, el niño de dos años que cayó a un pozo en #Totalán #Málaga el pasado domingo, trabaja de día y de noche sin descanso para rescatarlo lo antes posible. pic.twitter.com/O6J8c2kpVf
— Emergencias 112 (@E112Andalucia) January 15, 2019
Authorities said the difficult operation in the mountainous area was expected to take between 24 and 48 hours.
The narrow well was bored a month earlier during water prospection works and was not covered or protected, according to local media reports.