Understand the records

How tracking works

Every dot on the globe is an observation someone recorded and chose to release. Knowing how it was recorded tells you how far to trust it, and why there are gaps.

Observations, not live positions

An animal's tag does not stream its location to this application. Tags report when they can, projects process and sometimes delay those reports, and providers release them on their own schedule. We show two separate times for every record: when the animal was observed and when the record became available to us. "Latest report" always means the most recent observation the source has released, and we never present it as where the animal is now.

Satellite tags

Many marine animals carry tags that transmit to the Argos satellite system when the antenna breaks the surface. Each transmission yields a position with a location class that describes its accuracy: some are within a few hundred metres, others may be tens of kilometres off. Projects often run these raw positions through a movement model that estimates a smoother path; when a provider supplies such modelled positions we label them as provider modelled and draw them differently from directly observed fixes. GPS tags give far more precise points but drain batteries faster and still only report when they can see the sky.

Acoustic telemetry

Acoustic tags emit a coded ping that is heard by fixed receivers moored in the water. A detection tells you the animal passed within a few hundred metres of that receiver at that moment; it says nothing about where the animal was between receivers. We therefore plot detections at the receiver's location and connect them only as an approximate detection sequence, never as a measured track. Acoustic networks are collaborative: receivers are owned by many projects and data is matched and released through networks such as the Ocean Tracking Network and IMOS.

Light-based geolocation and archival tags

Some tags store data onboard and only release it when recovered or when the tag pops off and transmits a summary. Positions estimated from light levels can be hundreds of kilometres uncertain, particularly in latitude near the equinoxes. Where a provider shares these we show the published uncertainty and describe them as estimates.

Occurrence records

Biodiversity aggregators such as GBIF and OBIS publish occurrence records: a species observed at a place and time, from surveys, museum specimens, citizen science and tracking datasets alike. They are evidence that a species has been recorded somewhere, not a track of a particular animal, and some only carry a date or a year. We show them with their own symbol and precision.

Why there are gaps

• The tag could not transmit (submerged, under canopy, battery low).
• The project delays release, often by days or weeks, to protect animals or research priorities.
• The provider was unavailable, rate limited or changed its format and our connection paused rather than guess.
• Positions were generalised or withheld under a publication policy for a sensitive species or place.

Gaps are drawn as gaps. Replays move through the observation times that exist and never invent positions between them.

What we do with the records

We read only from sources whose terms permit it, keep every record's provenance and licence, apply each project's publication policy before anything is displayed, and compute derived figures such as distance between reported positions with documented, versioned methods. Tamara explains these records and cites the evidence she used. For the register of sources and their current status, see Sources.