Two years ago Israeli husband-and-wife directing team Yuval and Merav Nathan achieved worldwide acclaim with their stop-frame promo for Oren Lavie's Her Morning Elegance. Sixteen million YouTube views, awards and several commercials later they've made a follow-up, and its another stop-frame tour de force.

In their video for Israeli band Eatliz's Lose This Child, Yuval and Merav have recreated one of the most poignant phenomena in the natural world - the birth and gripping tale of a hatchling turtle's perilous race for survival of the hatchling turtle. And they've told this gripping tale purely in sand animation.

Yuval Nathan on making the video for Eatliz's Lose That Child

How did you come up with the idea to create a video about hatchling turtles And what came first, the decision to use sand or the idea about the turtles The idea of a turtle made out of sand, coming out of the sea has been in our ideas notebook for a long time and we were waiting for an opportunity to bring it to life. Since we live close to the sea, spend every summer on the beach playing with the children, the idea of animating sand on location was pretty natural for us as animators.

There is something really touching about sea turtles in nature. It is an animal that is not designed to walk on land. Despite its limitations, it instinctively crawls onto land to lay its eggs. It's hard not to feel empathy with those creatures. The turtle shape is also quite simple, and it is pretty easy to create and animate.

Where did you shoot it - was it all on location or did you composite bits together Most of the shots were shot on location on the shore. On the beach the sand is shaped by the humidity and wind. For example there are little ripples created by the wind and there can be a crust the salt and the sun. We also had few shots where we wanted to show the effect of the waves have on the sand.

The extreme close ups and the "singing Medusa" shots were shot in the studio so we could have better control of the grains. It meant we could work on a shot for few days since on the real beach, every day the sand looks different.

Most of the shots weren't composited, apart from the shots that were taken in the studio and had to have some sea background. We also did one 3D shot, which was the star turtles dancing in the sky.

What was sand like as a material to work with Did you have any expert sand sculptors on board or was it a case of learning as you went along The sand was a real challenge. We had to learn to deal with it throughout the shoot. The sand behaves differently in different levels of humidity and it gets dry under the lights. Sometimes a stiff crust can keep the sand beneath dry, and just a gentle touch can cause all of the sand to spill out of the sculpture. On the other hand the sand is very plastic. It keeps a pose and is easy to manipulate.

Another issue with the sand is its color. It's very monochromatic. For that reason we decided to work with hard lights, which create more defined dark and light areas. While animating we actually changed the silhouette of the elements in the picture by changing the angle of the surface toward the light. In some cases we used clay to support the form, for example, with the eel's heads.

The time-lapse shots of the sea and sky look otherworldly and magical. Was this something you planned We have experienced time lapses in past shoots, but this time since we were shooting at night, the camera also needed a longer exposure per picture. That caused the smearing effect of the wave's foam and the clouds. Adding this effect to the time lapse gave something of a dreamy ambience to the film.

There are some really nice moments - from the sky turtles and the little boy at the end... - which parts of the finished film are your personal favorites I feel that the strongest parts are the parts where I feel sympathy with the little turtle. For me, that happens when we're following the escaping turtle, and also during the close up of the turtle staring the stars. I also like the close up on the mother turtle when she starts digging.

Did you come across any unexpected challenges during the shoot If so how did you get round them We had to solve many problems that we couldn't plan for. We had to block the waves by digging canals and building walls. In other shots we had to carry buckets of water from the sea smooth the ground before every picture. Rafi Nathan the rigger and grip man [also Yuval's father] had to come up with several ingenious ideas, such as creating a ground level dolly in the sand to finding a solution to make the eel's head sink slowly into the wet sand at sunrise.

When you're working together, what's the division of labor like Do you tend to each keep to the same tasks on each job or do you chop and change or do everything together It changes from project to project. The concept, script and storyboarding we do together (in some cases we get script assistance from Nadav Ben Simon).

Merav is in charge on the design and Yuval is directing on the set and in charge on the animation (stop motion or 3D). We both do editing and compositing.