How Animals Navigate Using Stellar Cues

The most famous example of stellar navigation is found in night-migrating songbirds. In the 1960s, a landmark series of experiments conducted by Stephen Emlen [1] used a planetarium to test the orientation of North American Indigo Buntings.

Emlen discovered that these birds are not born with an innate map of the constellations. Instead, they must learn which way is north. They do this by observing the rotation of the night sky. In the Northern Hemisphere, all stars appear to rotate around a single fixed point: Polaris (the North Star). By identifying the one point in the sky that remains stationary while everything else moves, young birds calibrate their internal compass [2].

Key Bird Species Using Star Maps:

• Indigo Buntings: Use the center of celestial rotation to determine north/south axes.
• European Robins: Known to use stellar cues to calibrate their magnetic compasses [3].
• Garden Warblers: Use a combination of starlight and the Earth’s magnetic field to ensure accuracy during long-haul flights.

While birds focus on the rotation of specific stars, some creatures use much broader celestial features. The African dung beetle (Scarabaeus satyrus) is the first animal known to navigate using the Milky Way.

These beetles must roll a ball of dung away from a pile as quickly as possible to avoid theft by competitors. On moonless nights, they look up at the misty streak of light created by our galaxy [4]. According to research published by Marie Dacke at Lund University, dung beetles do not see individual stars. Instead, they perceive the Milky Way as a single, luminous gradient of light. As long as they maintain a consistent angle relative to that streak of light, they can travel in a perfectly straight line despite the pitch-black surroundings [5].

Until very recently, scientists believed only “higher” vertebrates like birds or humans could use the stars to navigate toward a specific geographical goal. However, a June 2025 study published in Nature [6] proved that the Australian Bogong moth uses a stellar compass for its 1,000-kilometer migration.

Researchers found that these moths utilize specific visual interneurons in their brains that are tuned to the orientation of the night sky. These neurons fire at maximum frequency when the moth is headed south, indicating an inherited “star-based” destination map. This discovery is incredibly significant because it shows that even insects with tiny brains can integrate magnetic and stellar cues to find a location they have never visited before.

Stellar navigation isn’t limited to the air and land. There is compelling evidence that marine mammals, specifically harbor seals, use the stars to stay on track during deep-sea foraging trips.

A study from the Marine Science Centre in Germany [4] trained harbor seals to swim toward specific “lodestars” (bright individual stars) in a floating planetarium. The seals were able to identify a single star out of a realistic projection of the Northern Hemisphere sky. This allows seals to maintain a straight course far from any terrestrial landmarks.

The evolution of these systems took millions of years, but human technology is threatening them in decades. As we explore in our article on how animal migration patterns impact global ecosystems, migration is a delicate balance.

Artificial light at night (ALAN) creates “skyglare” that obscures the dim light of stars and the Milky Way. When dung beetles are placed in urban environments like Johannesburg, they become completely disoriented because they can no longer see the galactic streak [7]. Similarly, migrating birds can become trapped in beams of light or lose their heading when city glow outshines the North Star.

The Mechanics of Navigation

• Rotation-Based: Birds observe sky movement over time to find the stationary celestial pole.
• Gradient-Based: Dung beetles use the broader glow of the Milky Way to roll in straight lines.
• Neural-Based: Moths have specific “compass neurons” that respond to the night sky’s orientation.
• Lodestar-Based: Marine mammals likely focus on a single bright star as a steering beacon.

Action Plan for Wildlife Protection

1. Reduce Light Pollution: Use shielded outdoor lighting that points downward to keep the night sky dark.
2. Support “Dark Sky” Initiatives: Advocate for the preservation of natural night environments in migratory corridors.
3. Timing Matters: Turn off non-essential lights during peak spring and autumn bird migration windows.
4. Scientific Awareness: Recognize that even “simple” insects require a clear view of the cosmos to survive.

Stellar navigation is one of nature’s most sophisticated survival strategies. From the tiny Bogong moth to the harbor seal, the ability to read the heavens is a testament to the complex sensory worlds animals inhabit—worlds we must work to protect as our own cities continue to brighten.