Mother-infant spatial relations in wild beluga (Delphinapterus leucas) during postnatal development under natural conditions

Annual calf indices for beluga whales, Delphinapterus leucas, in Cook Inlet Alaska, 2006-12

“…The calves in the June sample would be 10 to 12 months old while the calves in August would be zero to 2 months old. In August, this difference is particularly evident in the proximity 1 category (i.e., calf touching adult) which represented 40% of the calf sample (compared to 25% of the June calf sample) which is consistent with observations by Krasnova et al (2006) during which calves younger than 2 months were nearly always in contact with their mother.…”

“…Krasnova et al (2006) observed that very young calves may surface with the support of a submerged (thus invisible in Cook Inlet) mother, and therefore would appear to be alone (proximity 5) or if another adult was nearby to fall into proximity codes 2, 3, or 4. In addition, proximity codes 2, 3, and 4 could be affected by group behavior and density.…”

“…Young-of-the-year remain in close proximity to their mothers, and even at 1-2 months post-partum they are nearly always in contact with their mothers (Krasnova et al, 2006;Suydam, 2009). This proximity to an adult, and the size and color of these small whales (dark gray compared to the white adult), makes them more readily identifi able as calves.…”

“…Because the entire body of a beluga was not visible, given the turbid waters of the upper inlet, a "body length" was an approximation based on the average adult image size (i.e., amount of an adult's dorsal surface that was visible above the water). Krasnova et al (2006) examined the spatial relationship between beluga calves and their mothers within the fi rst 2 months post-partum. They found the most common positions during this developmental period were near the mother's fl ukes and at her side after comparing 11 behavioral elements.…”

Infant position in mother-calf dolphin pairs: formation locomotion with hydrodynamic benefits

“…This is true for cetacean calves, who have extremely limited locomotor performance (Noren et al 2006), yet at the same time must still maintain proximity to their mothers while she maneuvers within their habitat to forage and avoid predators. From the wild beluga whale Delphinapterus leucas (Krasnova et al 2006) to the Southern right whale Eubaleana australis (Taber & Thomas 1982) and captive and freeranging dolphins (McBride & Kritzler 1951, Tavolga & Essapian 1957, Norris & Prescott 1961, Au & Perryman 1982, Gubbins et al 1999, Mann & Smuts 1999, the predominant spatial states of mother-calf cetacean pairs are echelon position (calf in very close proximity to its mother's mid-lateral flank) and infant position (calf in very close positioning underneath its mother's tailstock; Fig. 1a, b) throughout the critical first year of development.…”