• Whale shark silhouettes scaled to measurements of various individuals reported in the literature and influenced by whale shark images found online.

• The smallest individual in the chart is based on measurements of a 'pup' described by Wolfson (1983), reported as 55 cm.^[1]

• The 'juvenile' individual is based on measurements in Silas & Rajagopalan (1963), reported as 5.62 m.^[2]

• Evidence from mainly male whale sharks suggests that they are sexually mature at around 8-9 m in length (9 m shown here). Females might mature at a similar size or larger.^[3][4][5]

• The 'large adult' silhouette is based primarily on measurements of a whale shark reported by Kaikini et al. (1959).^[6] Artists note; This whale shark was reported as 12.1 m in total length. However, the precaudal length was reported at 9.84 m, and the upper caudal fin was 2.31 m. Reaching the reported total length of 12.1 m would require the upper caudal fin to be illustrated at a shallow angle. This might imply it was measured as 'stretched total length' or over the body's curves.

• Whale sharks are sexually dimorphic regarding body size, with males reaching smaller sizes than females. Meekan et al. (2020) estimated that males reach an average of 8-9 m; this is an average, not the maximum possible size. There was less data for females, but Meekan et al. (2020) estimated an average of ~14.5 m.^[7]

• The largest size possible for whale sharks is uncertain. There are reports suggesting individuals around ~18-20 m, but many of these reports lack detailed measurements or documentation. The largest silhouette is scaled to 15 m standard length (precaudal length), based on an individual reported by Borrell et al. (2011). The total length was not documented; the authors estimated the total length at 18.8 m using an equation.^[8] McClain et al. (2015) considered this whale shark as the largest reliably measured.^[9]

• Note: There are several ways to measure a shark's total length. Some shark reports calculate the total length by adding the caudal fin to the pre-caudal length. Additionally, the whole shark can be measured by running a tape along the body's curves. Another way is by stretching the caudal fin to the maximum possible (referred to as stretched total length). These methods artificially increase the shark's total length when compared to how the shark measures in a natural posture. Another method is to try and pose the shark's tail fin in a natural position. However, for large sharks, this method is difficult to achieve. Any inaccuracy in the positioning of the tail can affect the reported total length measurement.^[10] The whale sharks in this image might not match the reported total length because of these issues.

• Human diver scaled to 180 cm (5 ft 11 in). Silhouette extracted from File:Sperm_whale_size.svg.

References