Michael Bull and colleagues followed marked shinglebacks in South Australian mallee for more than three decades, recording which animals were found together each spring. Pairs formed weeks before mating, with the male trailing a few centimetres behind the female for up to eight weeks, and the same two individuals re-formed in successive years. The longest documented partnerships ran over twenty seasons.
What this buys the animals is not fully settled. Proposed benefits include reduced time spent searching for a mate in a sparse population, better body condition in paired females, and vigilance while feeding. Genetic work has found that fidelity is not absolute; some clutches include offspring sired outside the pair, so social monogamy and genetic monogamy differ here as they do in birds.
Shinglebacks give birth to one to three very large live young rather than laying eggs, and adults have been recorded returning to a dead partner. That last observation is real but should not be read as evidence of grief, which the data cannot address.